Systems and methods for controlling flow from a wellbore annulus

ABSTRACT

A rotating control device for sealing an annulus includes an outer housing, and a seal assembly disposed within the outer housing and configured to seal against a rotating tubular member extending axially through a throughbore of the outer housing, wherein the seal assembly includes an inner housing, a first proximity sensor disposed along an inner surface of the outer housing, and a first sensor element disposed along an outer surface of the inner housing, wherein the first proximity sensor is configured to measure the rotational speed of the seal assembly in response to rotation of the seal assembly in the outer housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. provisional patent application Ser. No. 62/303,878 filed Mar. 4, 2016, and entitled “Systems and Methods for Controlling Flow from a Wellbore Annulus,” which is hereby incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND

Embodiments disclosed herein relate generally to oil and gas drilling and completion operations. More particularly, embodiments disclosed herein relate to systems and methods for controlling the flow of drilling fluid or mud from the annulus of a wellbore.

To drill a wellbore in an earthen formation to a subterranean reservoir, a drilling rig is positioned over the desired location of the wellbore and a drillstring suspended from the drilling rig through a blowout preventer (BOP) mounted to a wellhead at the surface and into the subterranean formation. During the drilling process, drilling fluid or mud is pumped through the drill string and exits the face of a drill bit connected to the lower end of the drillstring. The drilling fluid exiting the drill bit is recirculated to the surface via the annulus between the drillstring and the inner surface of the wellbore and then through the annulus between the drilling and the inner surface of the BOP. In onshore drilling applications, a rotating control device (RCD) is typically mounted to an upper end of the BOP and controls the flow and pressure of drilling fluid out the BOP annulus, and hence, control the flow and pressure of drilling fluid from the wellbore annulus. For instance, the RCD often includes an inner rotating seal for sealingly engaging the outer surface of the drillstring as the drillstring rotates and an annular outer seal that sealingly engages the BOP, thereby effectively capping the upper end of the annulus. The RCD may include one or more side outlets for allowing the passage of drilling fluid from the annulus of the wellbore.

Some offshore applications also include RCDs or similar devices for controlling flow and pressure from the annulus. For instance, in offshore applications, the drillstring typically extends from a drilling vessel at the surface of the water through a marine riser extending between the drilling vessel and the subsea BOP mounted to the wellhead at the sea floor into the wellbore. The recirculated drilling fluid flows through the wellbore annulus, the BOP annulus, and the annulus between the drillstring and the inner surface of the marine riser to the drilling vessel. In some applications, an RCD is coupled to an upper end of the marine riser proximal the drilling vessel. The RCD includes an inner rotating seal for sealingly engaging the outer surface of the drillstring as the drillstring rotates and an annular outer seal that sealingly engages the upper end of the marine riser, thereby effectively capping the upper end of the annulus in the marine riser, and hence, capping the BOP annulus and the wellbore annulus. The RCD may include one or more side outlets for allowing the passage of fluid from the annulus formed within the marine riser, or alternatively, a diverter spool may be provided below the RCD to provide a flowpath for drilling fluid flowing through the annulus in the marine riser.

SUMMARY

An embodiment of a rotating control device for sealing an annulus extending from a subterranean wellbore, the rotating control device comprises an outer housing including a central axis, a first end, a second end opposite the first end, an outer surface extending axially from the first end to the second end, and an inner surface extending axially from the first end to the second end, wherein the inner surface defines a throughbore extending axially through the outer housing, and wherein the outer housing comprises a plurality of circumferentially-spaced bores extending radially from the outer surface to the throughbore, a seal assembly disposed within the outer housing and configured to seal against a rotating tubular member extending axially through the throughbore of the outer housing, wherein the seal assembly comprises an outer surface including a receptacle, a plurality of actuatable locking pins, wherein each locking pin is moveably disposed in one of the bores of the outer housing and is configured to move radially relative to the outer housing between a locked position with a radially inner end the locking pin seated in the receptacle and an unlocked position with the radially inner end of the locking pin removed from the receptacle. In some embodiments, the inner surface of the outer housing comprises an annular shoulder configured to engage a mating annular shoulder on the outer surface of the seal assembly. In some embodiments, the annular shoulder of the outer housing comprises a frustoconical surface configured to slidingly engage a mating frustoconical surface of the annular shoulder of the seal assembly. In certain embodiments, the radially inner end of each locking pin comprises a chamfered profile configured to engage a corresponding chamfered profile of the outer surface of the seal assembly and urge the annular shoulder of the seal assembly in engagement with the annular shoulder of the outer housing. In certain embodiments, each locking pin comprises a fluid passage configured to be pressurized to transition the locking pin between the unlocked position and the locked position. In some embodiments, the rotating control device further comprises a position sensor disposed in one of the locking pins, wherein the position sensor is configured to output a signal indicating the position of the locking pin in the locked position or the unlocked position. In some embodiments, the rotating control device further comprises a stab plate coupled to the outer surface of the outer housing, wherein the stab plate comprises: a first fluid connector in fluid communication with a first fluid conduit, a second fluid connector in fluid communication with a second fluid conduit, and an electrical connector in signal communication with the position sensor, wherein at least one of the locking pins is configured to transition from the unlocked position to the locked position in response to pressurization of the first fluid conduit, wherein at least one of the locking pins is configured to transition from the locked position to the unlocked position in response to pressurization of the second fluid conduit. In certain embodiments, the radially inner end of each locking pin comprises a shoulder extending orthogonal the central axis of the outer housing. In certain embodiments, the outer housing includes a first passage extending from the inner surface to the outer surface and a second passage extending from the inner surface to the outer surface, the seal assembly comprises an inner housing including a first passage extending from an inner surface to an outer surface of the inner housing and a second passage extending from the inner surface to the outer surface of the inner housing, the first passage of the outer housing is in fluid communication with the first passage of the inner housing, and wherein the first passage of the outer housing and the first passage of the inner housing are configured to supply a lubricating fluid to a bearing chamber of the inner housing, and the second passage of the outer housing is in fluid communication with the second passage of the inner housing, and wherein the second passage of the outer housing and the second passage of the inner housing are configured to receive the lubricating fluid from the bearing chamber. In some embodiments, the first and second passages of the outer housing each include a check valve, and the first and second passages of the inner housing each include a check valve. In some embodiments, the rotating control device further comprises a first proximity sensor disposed along the inner surface of the outer housing, and a first sensor element disposed along an outer surface of an inner housing of the seal assembly, wherein the first proximity sensor is configured to measure the rotational speed of the seal assembly in response to rotation of the seal assembly in the outer housing. In some embodiments, the rotating control device further comprises a second proximity sensor disposed along the inner surface of the housing, and a second sensor element disposed along the outer surface of the inner housing, wherein the second sensor element is configured to detect a leak in a sealing element of the seal assembly in response to leakage across the sealing element.

An embodiment of a rotating control device for sealing an annulus extending from a subterranean wellbore, the rotating control device comprises an outer housing including a central axis, a first end, a second end opposite the first end, an outer surface extending axially from the first end to the second end, and an inner surface extending axially from the first end to the second end, wherein the inner surface defines a throughbore extending axially through the outer housing, and wherein the outer housing comprises a plurality of circumferentially-spaced bores extending radially from the outer surface to the throughbore, a plurality of actuatable locking pins, wherein each locking pin is moveably disposed in one of the bores of the outer housing and is configured to move radially relative to the outer housing between a locked position with a radially inner end the locking pin seated in the receptacle and an unlocked position with the radially inner end of the locking pin removed from the receptacle. In some embodiments, the rotating control device further comprises a seal assembly configured to be removably disposed within the outer housing, wherein the seal assembly comprises an outer surface including a receptacle configured to receive a radially inner end of each locking pin of the outer housing. In some embodiments, the seal assembly has a first position seated within the throughbore of the outer housing and a second position removed from the throughbore of the outer housing. In certain embodiments, the seal assembly is configured to be lowered into the throughbore of the outer housing at the first end of the outer housing. In certain embodiments, the inner surface of the outer housing comprises an annular shoulder and the outer surface of the seal assembly comprises an annular shoulder configured to axially abut the annular shoulder of the outer housing in the first position. In some embodiments, each locking pin comprises a fluid passage configured to be pressurized to transition the locking pin between the unlocked position and the locked position. In some embodiments, each locking pin comprises a position sensor configured to indicate the position of the locking pin in the locked position or the unlocked position.

An embodiment of a rotating control device for sealing an annulus extending from a subterranean wellbore comprises an outer housing including a central axis, a first end, a second end opposite the first end, an inner surface extending axially from the first end to the second end, and an outer surface extending between the first end and the second end, wherein the inner surface defines a throughbore extending axially through the outer housing, and wherein the outer housing includes a first passage extending from the inner surface to the outer surface and a second passage extending from the inner surface to the outer surface, and a seal assembly disposed within the outer housing and configured to seal against a rotating tubular member extending axially through the throughbore of the outer housing, wherein the seal assembly comprises an inner housing including a first end, a second end opposite the first end, an inner surface extending axially from the first end to the second end of the inner housing, and an outer surface extending between the first end and the second end of the inner housing, wherein the inner housing includes a first passage extending from the inner surface to the outer surface of the inner housing and a second passage extending from the inner surface to the outer surface of the inner housing, wherein the first passage of the outer housing is in fluid communication with the first passage of the inner housing, and wherein the first passage of the outer housing and the first passage of the inner housing are configured to supply a lubricating fluid to a bearing chamber of the inner housing, wherein the second passage of the outer housing is in fluid communication with the second passage of the inner housing, and wherein the second passage of the outer housing and the second passage of the inner housing are configured to receive the lubricating fluid from the bearing chamber. In some embodiments, the first and second passages of the outer housing each include a check valve, and the first and second passages of the inner housing each include a check valve. In some embodiments, the rotating control device further comprises a plurality of fluid conduits in fluid communication with the first and second passages of the outer housing, and a sensor coupled to one of the fluid conduits, wherein the sensor is configured to measure at least one of pressure and temperature of fluid disposed in the fluid conduit. In some embodiments, the rotating control device further comprises a stab plate coupled to the outer housing and including a fluid connector coupled to an end of one of the fluid conduits. In certain embodiments, the rotating control device further comprises a lubrication system coupled to the plurality of fluid conduits, wherein the lubrication system is configured to circulate lubricating fluid in a continuous circuit through the bearing chamber of the inner housing of the seal assembly. In certain embodiments, the rotating control device further comprises a sensor coupled to the outer housing and in fluid communication with the bore of the outer housing, wherein the sensor is configured to measure at least one of pressure and temperature of fluid disposed in the bore of the outer housing.

An embodiment of a rotating control device for sealing an annulus extending from a subterranean wellbore comprises an outer housing including a central axis, a first end, a second end opposite the first end, an inner surface extending axially from the first end to the second end, and an outer surface extending from the first end to the second end, wherein the inner surface defines a throughbore extending axially through the outer housing, and a seal assembly disposed within the outer housing and configured to seal against a rotating tubular member extending axially through the throughbore of the outer housing, wherein the seal assembly comprises an inner housing including a first end, a second end opposite the first end of the inner housing, an inner surface extending axially from the first end of the inner housing to the second end of the inner housing, and an outer surface extending from the first end of the inner housing to the second end of the inner housing, a first proximity sensor disposed along the inner surface of the outer housing, and a first sensor element disposed along the outer surface of the inner housing, wherein the first proximity sensor is configured to measure the rotational speed of the seal assembly in response to rotation of the seal assembly in the outer housing. In some embodiments, the first sensor element comprises a magnetic member. In some embodiments, the rotating control device further comprises a second proximity sensor disposed along the inner surface of the housing, a second sensor element disposed along the outer surface of the inner housing, wherein the second sensor element is configured to detect a leak in a sealing element of the seal assembly in response to leakage across the sealing element. In certain embodiments, the second sensor element comprises a sensor element assembly comprising: a housing, a piston slidably disposed in the housing, a biasing member configured to bias the piston towards a radially inner position, and a burst disc configured to rupture in response to leakage across the sealing element. In certain embodiments, in response to the rupture of the burst disc, the piston is configured to be actuated into a radially outer position. In some embodiments, in response to the piston of the sensor element assembly being disposed in the radially outer position, the second proximity sensor is configured to output a signal. In certain embodiments, the rotating control device further comprises a transducer disposed along the outer surface of a sleeve disposed in the inner housing of the seal assembly, wherein the transducer is configured to measure the pressure of fluid disposed in a bore of the sleeve, and a transmitter disposed along the inner surface of the outer housing, wherein the transducer is configured to wirelessly communicate signals indicative of the pressure of fluid disposed in the bore of the sleeve to the transmitter.

An embodiment of a method for sealing an annulus of a marine riser with a rotating control device (RCD) comprises (a) coupling an outer housing of the RCD to the marine riser, (b) lowering a seal assembly into the outer housing of the RCD after (a), wherein the seal assembly is configured to seal against a drillstring extending through the outer housing and the marine riser, and (c) extending a plurality of locking pins radially inward from the outer housing into a receptacle in an outer surface of the seal assembly after (b) to secure the seal assembly within the outer housing. In some embodiments, the method further comprises (d) flowing a fluid from an annulus disposed between the seal assembly and the outer housing through a port extending through the outer housing. In some embodiments, (b) comprises landing an annular landing profile of the seal assembly against a corresponding landing profile of the outer housing. In certain embodiments, (c) comprises engaging a chamfered profile of an inner end of each locking pin against a corresponding chamfered profile of the receptacle of the seal assembly. In certain embodiments, (c) comprises pressurizing a fluid passage extending through each locking pin to displace each locking pin into the receptacle of the outer surface of the seal assembly.

Embodiments described herein comprise a combination of features and advantages intended to address various shortcomings associated with certain prior devices, systems, and methods. The foregoing has outlined rather broadly the features and technical advantages of the invention in order that the detailed description of the invention that follows may be better understood. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of various exemplary embodiments, reference will now be made to the accompanying drawings in which:

FIG. 1 is a schematic view of an embodiment of an offshore drilling system in accordance with the principles disclosed herein;

FIG. 2 is a front view of the rotating control device (RCD) of FIG. 1;

FIG. 3 is a cross-sectional view of the RCD of FIG. 2 taken along section 3-3 of FIG. 2;

FIG. 4 is a front view of the seal assembly of the RCD of FIG. 2;

FIG. 5 is an exploded side view of the seal assembly of FIG. 4;

FIG. 6 is a cross-sectional view of the seal assembly of FIG. 4 taken along section 6-6 of FIG. 4;

FIG. 7 is a front view of one of the actuatable locking pins of the RCD of FIG. 2;

FIG. 8 is a cross-sectional view of the actuatable locking pin of FIG. 7 taken along section 8-8 of FIG. 7 and in a “locked” position;

FIG. 9 is a cross-sectional view of the actuatable locking pin of FIG. 7 taken along section 9-9 of FIG. 7 and in an “unlocked” position;

FIG. 10 is a schematic view of an embodiment of an offshore drilling system in accordance with the principles disclosed herein;

FIG. 11 is a perspective view of the RCD of FIG. 10;

FIG. 12 is a schematic top cross-sectional view of another embodiment of an RCD for use with either the offshore system of FIG. 1 or the offshore system of FIG. 10 in accordance with principles disclosed herein;

FIG. 13 is a schematic side cross-sectional view of another embodiment of an RCD for use with either the offshore system of FIG. 1 or the offshore system of FIG. 10 in accordance with principles disclosed herein;

FIG. 14 is a schematic top cross-sectional view of another embodiment of an RCD for use with either the offshore system of FIG. 1 or the offshore system of FIG. 10 in accordance with principles disclosed herein;

FIG. 15 is a schematic side cross-sectional view of the RCD of FIG. 14;

FIG. 16 is a schematic top cross-sectional view of another embodiment of an RCD shown in an unlocked position for use with either the offshore system of FIG. 1 or the offshore system of FIG. 10 in accordance with principles disclosed herein;

FIG. 17 is a schematic side cross-sectional view of the RCD of FIG. 16 shown in the unlocked position;

FIG. 18 is a schematic top cross-sectional view of the RCD of FIG. 16 shown in a locked position;

FIG. 19 is a schematic side cross-sectional view of the RCD of FIG. 16 shown in the locked position;

FIG. 20 is a side cross-sectional view of another embodiment of an RCD for use with either the offshore system of FIG. 1 or the offshore system of FIG. 10 in accordance with principles disclosed herein;

FIG. 21 is another side cross-sectional view of the RCD of FIG. 20;

FIG. 22 is a perspective view of another embodiment of an RCD for use with the offshore system shown in FIG. 1 in accordance with principles disclosed herein;

FIG. 23 is a first side cross-sectional view of the RCD of FIG. 22;

FIG. 24 is a second side cross-sectional view of the RCD of FIG. 22;

FIG. 25 is a third side cross-sectional view of the RCD of FIG. 22;

FIG. 26 is a zoomed-in cross-sectional view of the RCD of FIG. 22; and

FIG. 27 is another side cross-sectional view of the RCD of FIG. 22 including an embodiment of a protective sleeve in accordance with principles disclosed herein.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

The following discussion is directed to various exemplary embodiments. However, one skilled in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.

Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.

In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices, components, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis. As used herein, the term “well site personnel” is used broadly to include any individual or group of individuals who may be disposed or stationed on a rig or worksite or offsite at a remote monitoring location (such as a remote office location). The term also would include any personnel involved in the drilling and/or production operations at or for an oil and gas well such as, for example, technicians, operators, engineers, analysts, etc.

Referring now to FIG. 1, an embodiment of an offshore drilling system 10 for drilling a subsea wellbore 24 in an earthen formation 7 is shown. In this embodiment, system 10 generally includes a drilling vessel 12 disposed at the surface 3 of the water 3 (i.e., at the waterline), a wellhead 20 disposed at the sea floor 5, a BOP stack 56 mounted atop the wellhead 20, a lower marine riser package (LMRP) 54 mounted atop BOP stack 56, casing 24 extending from wellhead 20 into wellbore 24, and a marine riser system 30 extending from the drilling vessel 12 to LMRP 54. Wellbore 24, casing 24, wellhead 20, BOP stack 56, LMRP 54, and riser system 30 share a common, generally vertically oriented central or longitudinal axis 15.

Drilling vessel 12 includes a drilling floor 14 and a derrick 16 extending upwards from the drilling floor 14. In the embodiment shown in FIG. 1, drilling vessel 12 is a floating offshore structure, and more particularly, a floating semi-submersible platform. However, in other embodiments, the drilling vessel (e.g., vessel 12) may comprise other drilling vessels known in the art, such as drilling ships, tension leg platform, jack-up platform, and the like.

Marine riser system 30 provides a conduit for flowing drilling fluid or mud through the water between the drilling vessel 12 and the LMRP 54, BOP stack 56, and wellhead 24 disposed at the sea floor 5. More specifically, during drilling operations, drilling fluid is pumped from drilling vessel 12 down a drillstring 18 (shown with dashed lines) suspended from vessel 12 through marine riser system 30, LMRP 54, BOP stack 56, wellhead 20, and casing 24 into wellbore 22. The drilling fluid exits the drillstring 18 at a drill bit (not shown) connected to the lower end of drillstring 18 in the wellbore 24. Upon exiting the drillstring 18, the drilling fluid circulates back to the drilling vessel 12 through a series of contiguous, interconnected annuli radially positioned between drillstring 18 and the inner surfaces of wellbore 22, casing 24, wellhead 20, BOP stack 56, LMRP 54, and riser system 30.

Referring still to FIG. 1, and moving downward from vessel 12, in this embodiment, marine riser system 30 includes a diverter bowl 32 disposed just below and proximal drilling floor 14, a telescopic joint 34 having an upper end coupled to bowl 32, a tension ring 40 attached to joint 34, a rotating control device (RCD) 100 coupled to a lower end of joint 34, an annular blowout preventer (BOP) 44 coupled to RCD 100, a diverter spool 48 coupled to annular BOP 44, and a tubular marine riser 52 extending from annular BOP 44 to LMRP 54. Diverter bowl 32 defines the upper end of the marine riser system 30 and generally functions to divert annular flow (e.g., gas flows) during installation of marine riser system 30. Joint 34 includes an inner housing 36 and an outer housing 38 that can slide axially relative to each other, thereby allowing joint 34 to axially extend and contract. This functionality compensates for heave (relative vertical movement) between the marine riser system 30 and the drilling vessel 12. In this manner, heave experienced by drilling vessel 12 is accommodated without damaging components of marine riser system 30. In some embodiments, an annular packer is positioned between the inner housing 36 and the outer housing 38 to seal therebetween.

Tension ring 40 is disposed about and securely attached to the outside of outer housing 38 and suspended from a plurality of tension cables 42 extending from vessel 12. Thus, tension ring 40 and cables 42 support the components of marine riser system 30 suspended from outer housing 38 and apply tensile loads thereto.

RCD 100 is coupled to the lower end of telescopic joint 34. As will be described in more detail below, RCD 100 seals the upper end of the continuous annulus extending through marine riser system 30 from wellbore 24, thereby allowing flow of drilling fluid through the annulus to be controlled and pressurized. Annular BOP 44 is coupled to the lower end of RCD 100 and can be actuated in response to an uncontrolled influx of fluids from formation 7 into wellbore 24 to completely seal and close the annulus extending through marine riser system 30, thereby shutting in wellbore 24. A plurality of accumulators 46 are provided along riser system 30 for operating annular BOP 44. Accumulators 46 may also be utilized to actuate components of RCD 100, as will be discussed further herein.

Diverter spool 48 is coupled to the lower end of accumulators 46 and diverts fluid flowing through the annulus of marine riser system 30 to the drilling vessel 12. In particular, diverter spool 48 includes a plurality of circumferentially-spaced return conduits or lines 50 in fluid communication with the annulus. In this embodiment, return lines 50 are in the form of goosenecks extending from diverter spool 48 to vessel 12. Thus, drilling fluid flowing through the annulus of marine riser system 30 can be selectively directed to drilling vessel 12 via the plurality of return conduits 50. In this embodiment, each return conduit 50 includes one or more valves (not shown) that can be opened or closed to permit or prevent, respectively, fluid flow therethrough. Due to the seal provided by RCD 100 at the upper end of riser system 30, and provided one or more of the vales in return conduits 50 are open, fluid flowing through the annulus of marine riser 30 is forced to flow through return conduits 50 to drilling vessel 12. At drilling vessel 12, the drilling fluid is cleaned and conditioned to remove any cuttings or other contaminants, and then pumped back down drillstring 18.

Referring now to FIGS. 2-5, in this embodiment, RCD 100 has a central or longitudinal axis 105 coaxially aligned with axis 15 of riser system 30 and generally includes an outer housing 102, a rotating or rotatable seal assembly 130 slidingly received within outer housing 102, and a plurality of circumferentially-spaced actuatable locking pins 310 that selectively lock seal assembly 130 within outer housing 102. Outer housing 102 includes a first or upper end 102 a, a second or lower end 102 b, an inner surface 106 extending between ends 102 a, 102 b, and an outer surface 108 extending axially between ends 102 a, 102 b. Inner surface 106 defines a central throughbore 104 extending axially through housing 102 (i.e., between ends 102 a, 102 b). An annular connection flange 110 is provided at upper end 102 a and lower end 102 b. Each connection flange 110 includes an annular seal assembly 112 comprising an annular groove that receives an annular seal member for sealing against mating flanges provided on the adjacent components of marine riser system 30.

In this embodiment, outer housing 102 also includes a plurality of uniformly circumferentially spaced bores 114 extending radially through housing 102 from outer surface 108 to inner surface 106. Although bores 114 are shown as being generally cylindrical in FIGS. 2-5, in other embodiments, bores 114 may include varying cross-sectional shapes (e.g., square, rectangular, hexagonal, etc.). An annular recess is provided on outer surface 108 at the radially outer end of each bore 114. One locking pin 310 is disposed in each bore 114. In this embodiment, inner surface 106 of outer housing 102 includes an annular frustoconical, generally upward facing landing surface 118 axially positioned below and adjacent bores 114. However, in other embodiments, landing surface 118 need not be frustoconical in shape. Landing surface 118 is disposed at an acute angle a relative to axis 105. In embodiments described herein, angle a is preferably between 0° and 90°, and more preferably about 30°. Seal assembly 130 is sized and shaped to seat against mating landing surface 118.

Referring now to FIGS. 3-5, seal assembly 130 seals against the outer surface of drillstring 18 as drillstring 18 is both rotated about its longitudinal axis and advanced axially (with respect to axes 15, 105) through marine riser system 30. In this embodiment, seal assembly 130 is installed in outer housing 102 after installation of outer housing 102 along marine riser system 30. Particularly, outer housing 102 of RCD 100 is coupled to telescopic joint 34 and annular BOP 44, and then RCD 100 is displaced beneath the drill floor 14 of drilling vessel 12 as shown in FIG. 1. Next, seal assembly 130 is inserted into outer housing 102 utilizing a running tool or drill string, and then secured within outer housing 102 with the plurality of locking pins 310. Likewise, seal assembly 130 can be removed from outer housing 102 using the running tool or drill string while outer housing 102 remains in place as part of marine riser system 30.

In this embodiment, seal assembly 130 is coaxially aligned with axis 105 and generally includes a housing assembly 132, a rotating or rotatable sleeve assembly 180 radially disposed within housing assembly 132, and a bearing assembly 230 radially disposed between assemblies 132, 189. Housing assembly 132 includes a first or upper housing member 134 and a second or lower housing member 150 secured to upper housing member 134 with bolts. As best shown in FIG. 3, housing assembly 132 lands within outer housing 102 and is releasably locked therein by pins 310, thereby releasably securing seal assembly 130 with outer housing 102.

Upper housing member 134 of housing assembly 132 has a first or upper end 134 a defining the upper end of seal assembly 130, a second or lower end 134 b opposite upper end 134 a, an inner surface 138 extending axially between ends 134 a, 134 b, and an outer surface 140 extending axially between ends 134 a, 134 b. Inner surface 138 defines a throughbore 136 extending axially through housing member 134. Upper housing member 134 also includes a radially outer flanged section 142 at upper end 134 a that forms an annular downward facing shoulder 142 s that axially abuts lower housing member 150. In addition, upper housing member 134 includes a plurality of circumferentially spaced radial lubrication ports 146 proximal lower end 134 b. Each port 146 extends radially between surfaces 138, 140. Ports 146 allow for the passage of lubricant to bearing assembly 230. Upper housing member 134 further includes an annular seal groove 148 extending into outer surface 140 and disposed adjacently above (i.e., closer to upper end 134 a) radial ports 146. An annular seal member is disposed in groove 148 and sealingly engages lower housing member 150.

A plurality of circumferentially-spaced apertures 145 extend axially upward into flanged section 142. Each aperture 145 receives a releasable fastener for coupling a retainer ring 147 to the lower end of flanged section 142. The coupling of retainer ring 147 to the lower end of flanged section 142 forms an annular groove extending into the inner surface 138 of upper housing member 134, where the annular groove is configured to receive a rotary seal 149 for sealingly engaging the rotating sleeve assembly 180 as sleeve assembly 180 rotated within housing assembly 132.

Referring still to FIGS. 3-5, lower housing member 150 has a first or upper end 150 a, a second or lower end 150 b, an inner surface 154 extending axially between ends 150 a, 150 b, and an outer surface 156 extending axially between ends 150 a, 150 b. Inner surface 154 defines a throughbore 152 extending axially through member 150. In this embodiment, inner surface 154 includes a reduced diameter section 158 radially adjacent rotating sleeve assembly 180. Reduced diameter section 158 prevents axial misalignment of rotating sleeve assembly 180 and bearing assembly 230 with longitudinal axis 105 of RCD 100. Particularly, reduced diameter section 158 prevents rotating sleeve assembly 180 and bearing assembly 230 from shifting angularly within outer housing 102, or in other words, prevents a longitudinal axis of rotating sleeve assembly 180 and bearing assembly 230 from being disposed at an angle relative longitudinal axis 105. In addition, the inner surface 154 includes an annular seal groove 162 disposed proximal upper end 150 a. An annular seal member is disposed in groove 162 and sealingly engages the outer surface 140 of upper housing member 134. Thus, radial ports 146 of upper housing member 134 are axially flanked by seal groove 148 (and associated seal member) of upper housing member 134 and seal groove 162 (and associated seal member) of lower housing member 150, thereby sealing radial ports 146 from the surrounding environment. Inner surface 154 further includes an annular shoulder 163 facing the upper end 150 a of lower housing 150.

The outer surface 156 of lower housing member 150 includes a landing profile 164 having frustoconical surface 165 for engaging mating landing surface 118 of outer housing 102. Thus, in this embodiment, landing surface 165 of lower housing member 150 is disposed at the same angle a relative to axis 105 as landing surface 118. Outer surface 156 also includes an annular groove or receptacle 166 and disposed axially between upper end 150 a and landing profile 164. Annular groove 166 is sized and positioned to receive locking pins 310 for releasably locking seal assembly 130 to outer housing 102. In particular, annular groove 166 includes an annular angled or chamfered profile 167 for slidingly engaging a corresponding landing profile of the actuatable locking pins 310. However, in other embodiments, annular groove 166 need not include chamfered profile 167. A pair of annular seal assemblies 168 are provided axially below groove 166 and radially between outer surface 156 of lower housing member 150 and inner surface 106 of outer housing 120 for sealing therebetween.

In this embodiment, lower housing member 150 further includes a plurality of apertures 170 extending into lower end 150 b that are aligned with, but radially offset from longitudinal axis 105. Each aperture 170 receives a releasable fastener for coupling a retainer ring 172 to the lower end 150 b of lower housing member 150. The coupling of retainer ring 172 to the lower end 150 b of lower housing member 150 forms an annular groove extending into the inner surface 154 of lower housing member 150, where the annular groove is configured to receive a rotary seal 174 for sealingly engaging the rotating sleeve assembly 180 as sleeve assembly 180 rotated within housing assembly 132. Thus, rotary seal 174 and annular seals 168 act in conjunction to restrict fluid communication or a fluid flow through throughbore 104 of outer housing 102 that does not pass through rotating sleeve assembly 180, thereby sealing an annulus 103 disposed between rotating sleeve assembly 180 and the outer housing 102.

Referring now to FIGS. 3, 5, and 6, rotating sleeve assembly 180 seals against the outer surface drillstring 18 as it both rotates and move axially through sleeve assembly 180. Rotating sleeve assembly 180 rotates relative to housing assembly 132 via bearing assembly 230. In this embodiment, rotating sleeve assembly 180 has a longitudinal axis disposed coaxially aligned with axis 105 and generally includes a rotating sleeve 182, an annular mounting member 200, and a sealing member or boot 210.

Rotating sleeve 182 couples rotating sleeve assembly 180 with bearing assembly 230, which is in turn supported by housing assembly 132. Rotating sleeve 182 has a first or upper end 182 a, a second or lower end 182 b, an inner surface 186 extending axially between ends 182 a, 182 b, and an outer surface 188 extending axially between ends 182 a, 182 b. Inner surface 186 defines a central throughbore 184 extending through sleeve 182. Outer surface 188 includes a first or upper annular groove 190 disposed proximal upper end 182 a and a second or lower annular groove 192 disposed proximal lower end 182 b. Annular grooves 182 a, 182 b secure components of bearing assembly 230 to rotating sleeve 182. Rotating sleeve 182 also includes a radially outer flanged section 194 at lower end 182 b for securing sleeve 182 to mounting member 200. In this embodiment, flanged section 194 includes an annular seal groove 196 extending axially into rotating sleeve 182 at lower end 182 b. An annular seal member is disposed in grove 196 and sealingly engages mounting member 200.

Mounting member 200 of rotating sleeve assembly 180 physically supports and couples sealing boot 210 with rotating sleeve 182. In this embodiment, mounting member 200 has a first or upper end 200 a, a second or lower end 200 b, and a radially outer flanged section 202 disposed at upper end 200 a. Flanged section 202 includes a plurality of circumferentially spaced apertures (not shown) for receiving fasteners that secure mounting member 200 to rotating sleeve 182. In this embodiment, the upper end 200 a of mounting member 200 also includes an annular seal groove 204 axially opposed with seal groove 196 of rotating sleeve 182. The annular seal member disposed in groove 196 extends into grove 204 and forms an annular seal between mounting member 200 and rotating sleeve 182.

Sealing boot 210 comprises a durable, resilient elastomeric material sized and configured to sealingly engage the outer surface of drillstring 18 extending therethrough. Sealing boot 210 has a first or upper end 210 a, a second or lower end 210 b, a central throughbore 212 extending axially between ends 210 a, 210 b, and an outer surface 216 extending axially between ends 210 a, 210 b. The inner surface of boot 210 that defines throughbore 212 includes a frustoconical surface axially positioned between ends 210 a, 210 b. Thus, the diameter of throughbore 212, and hence the inner diameter of boot 210, generally decreases moving from upper end 210 a toward lower end 210 b. In this embodiment, sealing boot 210 is molded onto mounting member 200 such that sealing boot 210 is fixably secured to and supported by mounting member 200. Further, because the lower end 200 b of mounting member 200 does not extend to lower end 210 b of sealing boot 210, the portion of sealing boot 210 proximal lower end 210 b is unsupported by mounting member 200, providing greater flexibility to the portion of sealing boot 210 proximal lower end 210 b.

Given the flexibility and resiliency of the lower end 210 b of sealing boot 210, the inner surface 214 of sealing boot 210 can maintain a continuous seal against the outer surface of drillstring 18, even if the outer surface of drillstring 18 varies in diameter along its longitudinal length. For instance, in some applications, drillstring 18 comprises a plurality of discrete tubular members or drill pipes threadably connected end-to-end at pipe joints, where each pipe joint has a greater outer diameter than the “shank” or body of each individual drill pipe. Thus, in order to maintain a continuous seal against the outer surface of drillstring 18, the diameter 218 of throughbore 212 proximal lower end 210 b must expand radially outwards to account for the greater outer diameter of each tool joint as drillstring 18 is displaced longitudinally through throughbore 104 of outer housing 102. To assist in allowing the lower end 210 b of sealing boot 210 to expand radially outwards to account for larger diameter tool joints, sealing boot 210 includes a plurality of longitudinally extending (i.e., extending parallel with longitudinal axis 105) grooves 220 (shown in FIG. 4) that extend radially into outer surface 216. In this manner, when the lower end 210 b of sealing boot 210 to expands for a tool joint or other larger diameter section of drillstring 18, material comprising sealing boot 210 may flow into longitudinal grooves 220, allowing inner surface 214 to maintain a seal against the outer surface of the variable outer diameter of drillstring 18.

Referring still to FIGS. 3, 5, and 6, bearing assembly 230 of RCD 100 allows for the rotation of rotating sleeve assembly 180 about longitudinal axis 105 as drillstring 18 rotates and moves axially through sleeve assembly 180. In this embodiment, bearing assembly 230 has a central or longitudinal axis coaxially aligned with axis 105 and generally includes a first or upper annular retainer 232, a second or lower annular retainer 240, a first or upper inner annular bearing race 250, an annular bearing spacer 260, a second or lower annular inner bearing race 270, a first or upper plurality of conical roller bearings 280, a second or lower plurality of conical roller bearings 284, and an outer annular bearing race 290.

Upper retainer 232 and lower retainer 242 physically support the other components of bearing assembly 230 and restrict relative axial movement between bearing assembly 230 and rotating sleeve assembly 180 via coupling with rotating sleeve assembly 180. In this embodiment, upper retainer 232 includes a first or upper end 232 a, a second or lower end 232 b, and a central throughbore 234 extending axially between ends 232 a, 232 b. Upper retainer 232 also includes a plurality of circumferentially spaced apertures 236 disposed proximal upper end 232 a and extending radially therethrough. Each aperture 236 is configured to receive a corresponding pin that extends therethrough and into upper annular groove 190 of rotating sleeve 182 to restrict relative axial movement between upper retainer 232 and rotating sleeve 182. Similarly, lower retainer 240 includes a first or upper end 240 a, a second or lower end 240 b, and a central throughbore 242 extending axially between ends 240 a, 240 b. Lower retainer 240 also includes a plurality of circumferentially spaced apertures 244 disposed proximal upper end 240 a and extending radially therethrough. Each aperture 244 is configured to receive a corresponding pin that extends therethrough and into lower annular groove 192 of rotating sleeve 182 to restrict relative axial movement between lower retainer 240 and rotating sleeve 182.

Bearing races 250, 270, 290 physically support and position upper roller bearings 280 and lower bearings 284. Bearing races 250, 270, 290 also transmit both radial and axial thrust loads applied to bearings 280, 284 to housing assembly 132. In this embodiment, upper bearing race 250 has a first or upper end 250 a, a second or lower end 250 b, and a throughbore 252 extending axially between ends 250 a, 250 b. The upper end 250 a of upper bearing race 250 engages the lower end 232 b of upper retainer 232, while the lower end 250 b of upper bearing race 250 engages bearing spacer 260, thereby restricting axial movement of upper bearing race 250. Upper bearing race 250 also includes an inclined bearing seat 254 that extends into an outer surface of upper bearing race 250.

Inclined bearing seat 254 positions the upper roller bearings 280 such that a longitudinal axis of each upper roller bearing 280 is disposed at an angle relative longitudinal axis 105. In this arrangement, both radial and thrust loads may be transferred from upper bearing race 250 to upper roller bearings 280, and from upper roller bearings 280 to outer bearing race 290. Particularly, upper roller bearings 280 are inclined via inclined seat 254 such that axial thrust loads in the downward direction are transferred between upper bearing race 250 and outer bearing race 290 via upper roller bearings 280.

Axially positioned between upper bearing race 250 and lower bearing race 270 is bearing spacer 260, which spaces upper roller bearings 280 apart from lower roller bearings 284. In this embodiment, bearing spacer 260 has a first or upper end 260 a, a second or lower end 260 b, and a central throughbore 262 extending axially between ends 260 a, 260 b. As mentioned above, the upper end 260 a of bearing spacer 260 engages the lower end 250 b of upper bearing race 250 to assist in positioning upper bearing race 250.

In this embodiment, lower bearing race 270 has a first or upper end 270 a, a second or lower end 270 b, and a throughbore 272 extending axially between ends 270 a, 270 b. Upper end 270 a engages the lower end 260 b of bearing spacer 260, while the lower end 270 b engages the upper end 240 a of lower retainer 240, thereby restricting axial movement of lower bearing race 270. Lower bearing race 270 also includes an inclined bearing seat 274 that extends into an outer surface of lower bearing race 270. Inclined bearing seat 274 positions the lower plurality of roller bearings 284 such that a longitudinal axis of each lower roller bearing 284 is disposed at an angle relative longitudinal axis 105 of RCD 100. In this arrangement, lower roller bearings 284 are inclined via inclined seat 274 such that axial thrust loads in the upward direction are transferred between lower bearing race 270 and outer bearing race 290 via lower roller bearings 284.

Outer bearing race 290 is disposed radially about upper bearing race 250, lower bearing race 270, and roller bearings 280, 284. Outer bearing race 290 supports upper roller bearings 280 and lower roller bearings 284, and transfers radial and axial thrust loads imparted to roller bearings 280, 284 to the lower housing member 150 of housing assembly 132. In this embodiment, outer bearing race 290 has a first or upper end 290 a, a second or lower end 290 b, and a throughbore 292 extending between upper end 290 a and lower end 290 b, where throughbore 292 is defined by an inner surface 294. In the embodiment shown, the lower end 290 b of outer bearing race 290 is seated against the annular shoulder 163 of lower housing member 154 for physically supporting seal assembly 130 within outer housing 102. In this embodiment, the inner surface 294 of outer bearing race 290 includes a first or upper inclined section 296, and a second or lower inclined section 298. Both inclined sections 296, 298 are disposed at an angle β relative longitudinal axis 105. Particularly, upper inclined section 296 is disposed at the same angle β relative to axis 105 as upper roller bearings 280, and thereby receives radial loads and axial thrust loads in the downwards direction from upper roller bearings 280. Similarly, lower inclined section 298 is disposed at the same angle β relative to axis 105 as lower roller bearings 284, and thereby receives radial loads and axial thrust loads in the upwards direction from lower roller bearings 284. In embodiments described herein, angle 13 may comprise an angle between 5° and 30°.

Referring now to FIGS. 7-9, actuatable locking pins 310 selectively lock seal assembly 130 within outer housing 102, thereby preventing relative axial movement therebetween. In this embodiment, locking pins 310 are hydraulically actuated via hydraulic lines (not shown) extending between drilling vessel 12 and RCD 100. In other embodiments, the locking pins 310 receive hydraulic pressure from other sources, such as accumulators 46 previously described and shown in FIG. 1.

Each actuatable locking pin 310 has a radially oriented central or longitudinal axis 315 that intersects axis 105. In this embodiment, each actuatable locking pin 310 is the same, and thus, one pin 310 will be described it being understood the other pins 310 are the same. Locking pin 310 generally includes an outer housing 312 and a sliding pin 350 disposed within outer housing 312. Outer housing 312 includes a first or inner housing member 314 and a second or outer housing member 330. Inner housing member 314 has a first or radially outer end 314 a (relative to axis 105), a second or radially inner end 314 b (relative to axis 105), a generally cylindrical inner surface 318 extending axially (relative to axis 315) between ends 314 a, 314 b, and a generally cylindrical outer surface 320 extending axially (relative to axis 315) between ends 314 a, 314 b. Inner surface 318 defines a central throughbore 316 extending axially through the corresponding pin 310.

In this embodiment, the outer surface 320 of inner housing member 314 includes a threaded connector 320t for threadably engaging a corresponding threaded connector 114t disposed on the inner surface of bore 114 of outer housing 102, thereby releasably coupling locking pin 310 to outer housing 102. A pair of axially spaced annular seals 322 are disposed in corresponding annular grooves along outer surface 320. Seals 322 sealingly engage the inner surface of bore 114 of outer housing 102. Inner surface 318 includes an annular shoulder 324 facing outer housing member 330. Inner housing member 314 also includes a radially outwards flanged section 326 for engaging outer housing member 330.

Outer housing member 330 releasably couples with inner housing member 314 and includes a first or radially outer end 330 a (relative to axis 105), a second or radially inner end 330 b (relative to axis 105), a generally cylindrical inner surface 334 extending axially (relative to axis 315) between ends 330 a, 330 b, and a generally cylindrical outer surface 336 extending axially (relative to axis 315) between ends 330 a, 330 b. Inner surface 334 defines a central throughbore 332 extending axially through outer housing member 330. An annular seal 338 is disposed in an annular groove disposed along inner surface 334. Seal 338 sealingly engages the outer surface of sliding pin 350. In addition, inner surface 334 includes an annular shoulder 340 facing inner housing member 314.

An annular seal 342 is disposed in an annular groove along outer surface 336. Seal 342 sealingly engages inner housing member 314. In addition, outer housing member 330 includes a radially outer flanged section 344 disposed proximal inner end 330 b. Housing members 330, 314 are releasably coupled by a plurality of circumferentially-spaced fasteners 346 extending through opposed flanged sections 344, 326

As best shown in FIGS. 8 and 9, sliding pin 350 is slidably disposed within outer housing 312 and has a first or radially outer end 350 a (relative to axis 105), a second or radially inner end 350 b (relative to axis 105), and a generally cylindrical outer surface 352 extending axially (relative to axis 315) between ends 350 a, 350 b. In this embodiment, three annular seals are provided along the outer surface 352 of sliding pin 350—a first annular seal 354 disposed proximal inner end 350 b, a second annular seal 356 disposed proximal outer end 350 a, and a third annular seal 358 disposed axially (relative to axis 315) between seals 354, 356. Each seal 354, 356, 358 is disposed in corresponding annular groove in outer surface 352. In this arrangement, first seal 354 and third seal 358 sealingly engage the inner surface 318 of inner housing member 314 while second seal 356 sealingly engages the inner surface 334 of outer housing member 330.

The outer surface 352 of sliding pin 350 also includes an inclined or chamfered profile 360 at inner end 350 b. However, in other embodiments, sliding pin 350 need not include chamfered profile 360. In this embodiment, chamfered profile 360 mates and slidingly engages the corresponding chamfered profile 167 of lower housing member 150. In this arrangement, when chamfered profile 360 of sliding pin 350 physically engages chamfered profile 167, housing assembly 132 is urged axially downward (relative to axis 105), thereby increasing the force or pressure between the landing profile 164 of lower housing member 150 and the landing surface 118 of outer housing 102. Thus, the chamfered action or interface between sliding pin 350 and lower housing member 150 increases the seating force between housing assembly 132 and outer housing 102. The outer surface 352 of sliding pin 350 also includes a first annular shoulder 362 facing inner end 350 b and a second annular shoulder 364 spaced from first shoulder 362 and facing outer end 350 a.

In this embodiment, sliding pin 350 includes a plurality of fluid passages for routing pressurized fluid for actuating sliding pin 350 between a first or “locked” position shown in FIG. 8, and a second or “unlocked” position in FIG. 9. Specifically, sliding pin 350 includes a first or opening passage 366, a second or closing passage 368, and a lubrication passage 370, each passage 366, 368, 370 extending between outer end 350 a and outer surface 352. More specifically, a terminal end 366 a of opening passage 366 is disposed between first seal 354 and third seal 358, a terminal end 368 a of closing passage 368 is disposed between second seal 356 and third seal 358, and a terminal end 370 a of lubrication passage 370 is disposed between second seal 356 and third seal 358. End 358 a of closing passage 368 is disposed between ends 366 a, 370 a of passages 366 and 370.

As shown particularly in FIG. 8, in the locked position, the inner end 350 b of sliding pin 350 is disposed within and fully seated in mating annular groove 166 of lower housing member 150 with chamfered profile 360 of sliding pin 360 engaging mating chamfered profile 167 of annular groove 166. In addition, in the locked position, annular shoulder 324 of inner housing member 314 axially abuts first shoulder 362 of sliding pin 350, while second shoulder 364 of sliding pin 350 is spaced apart from shoulder 340 of outer housing member 330. In the unlocked positon shown in FIG. 9, the inner end 350 b of sliding pin 350 is completely removed from annular groove 166 of lower housing member 150, and chamfered profile 360 of sliding pin 360 is spaced apart from mating chamfered profile 167 of annular groove 166. In addition, in the unlocked position, annular shoulder 324 of inner housing member 314 is spaced apart from first shoulder 362 of sliding pin 350, while second shoulder 364 of sliding pin 350 axially abuts shoulder 340 of outer housing member 330.

Sliding pin 350 can be actuated from the unlocked position shown in FIG. 9 to the locked position shown in FIG. 8 by depressurizing passage 366 and flowing a pressurized fluid into or otherwise pressurizing closing passage 368, which applies a fluid pressure against the annular shoulder 340 of outer housing member 330 and second shoulder 364 of sliding pin 350, thereby axially displacing sliding pin 350 through outer housing 312 until chamfered profile 360 of sliding pin 350 matingly engages the chamfered profile 167 of lower housing member 150. In some embodiments, passage 366 is depressurized by flowing fluid into end 366 a of passages 368 from throughbore 316 of inner housing member 314, and then flowing the fluid passing through end 366 a out of passage 366 to reduce the fluid pressure therein. The reduction of fluid pressure in passage 366 prevents hydraulic lock from restricting the displacement of sliding pin 350 through outer housing 312.

In some embodiments, a pilot valve (not shown) is connected between closing passage 368 and the fluid or pressure source in fluid communication with and configured to pressurized closing passage 368. In this arrangement, the pilot valve is configured to prevent inadvertent depressurization of closing passage 368 and subsequent actuation of sliding pin 350 from the locked position to the unlocked position. Particularly, the pilot valve is configured to allow for the communication of fluid or fluid pressure to closing passage 368 while restricting the depressurization or fluid flow out of closing passage 368 unless a separate pressure or electric signal is communicated to the pilot valve to actuate the pilot valve and thereby depressurize closing passage 368. Therefore, in the event of a reduction in the fluid pressure applied to closing passage 368, closing passage 368 would remain pressurized with sliding pin 350 held in the locked position until either a positive pressure or electric signal is communicated to the pilot valve to release the fluid pressure retained within closing passage 368. In this manner, sliding pin 350 will remain in the locked position coupling or locking seal assembly 130 within outer housing 102 even if fluid pressure in communication with closing passage 368 is inadvertently lost or reduced.

Sliding pin 350 can be actuated from the locked position shown in FIG. 8 into the unlocked positon shown in FIG. 9 by depressurizing passage 368 and then flowing a pressurized fluid into opening passage 366, which applies a fluid pressure against the annular shoulder 324 of inner housing member 314 and first shoulder 362 of sliding pin 350, thereby axially displacing sliding pin 350 through outer housing 312 until second shoulder 364 of sliding pin 350 engages the shoulder 340 of outer housing member 330. Particularly, the pressure applied to closing passage 368 is reduced and a pressure or electric signal is communicated to the pilot valve in fluid communication with passage 368 to thereby allow pressure trapped within passage 368 by the pilot valve to be vented therefrom. Passage 368 is depressurized to prevent hydraulic lock from restricting the movement of sliding pin 350, and passage 368 may be depressurized in a manner similar to that described above with respect to passage 366. Although sliding pins 350 are described above as actuated in response to a fluid pressurization or fluid flow, in other embodiments, sliding pins 350 may be actuated pneumatically or via an electrical actuator.

Lubrication passage 370 is configured to provide a fluid passage for the application of a lubricant between the outer surface 352 of sliding pin 350 and the inner surface 334 of outer housing member 330 to minimize friction therebetween as sliding pin 350 is actuated between the locked and unlocked positions. Thus, during operation of RCD 100 lubrication passage 370 remains depressurized to prevent hydraulic lock from restricting the actuation of sliding pin 350. In some embodiments, a grease gun or other lubricant delivery system may be placed in fluid communication with lubrication passage 370 such that lubricant may be flowed through passage 370 and applied between the surface 352 and 334. As shown in FIGS. 8 and 9, the terminal end 370 a of lubrication passage 370 is disposed between annular seal 356 of sliding pin 350 and the annular seal 338 of outer housing 330 when sliding pin is in either the locked or unlocked positions, preventing the lubricant passing through terminal end 370 a from mixing with hydraulic fluid in communication with passages 366 and 368.

Referring now to FIG. 10, another embodiment of an offshore well system 400 for drilling a subsea wellbore 24 is shown. Offshore system 400 shares many features in common with offshore system 10 discussed above. Such shared features are labeled similarly. In this embodiment, offshore system 400 has a generally vertically oriented central or longitudinal axis 415 and includes a marine riser system 410, LMRP 54, and BOP stack 56. Marine riser system 410 is substantially the same as riser system 30 previously described. In particular, marine riser system 410 includes a diverter bowl 32, a telescopic joint 34, a tension ring 40, an annular BOP 44, accumulators 46, and a riser 52, each as previously described. However, in this embodiment, riser system 410 includes a rotating control device (RCD) 500 positioned above tension ring 40 (instead of RCD 100), and further, no diverter spool 48 is provided. Return conduits 50 previously provided in connection with diverter spool 48 are replaced with a plurality of side outlets or return lines 502 extending from RCD 500. Similar to return conduits 50, return conduits 502 of RCD 500 provide a flow path for drilling fluid in the annulus to return to drilling vessel 12. Thus, in this embodiment, drilling fluid returns from wellbore 24 pass through the annulus within riser system 410 to RCD 500, and are routed directly from RCD 500 through return conduits 502 extending therefrom to vessel 12. In this manner, the side outlets of RCD 500 and associated return conduits 502 replace the functionality of diverter spool 48 and return conduits 50 of marine riser system 30.

Referring now to FIG. 11, RCD 500 shares many features in common with RCD 100 discussed above. Such shared features are labeled similarly. In this embodiment, RCD 500 has a central or longitudinal axis 505 coaxially aligned with axis 415 and generally includes an outer housing 504, a seal assembly 130 disposed within outer housing 504, and a plurality of actuatable locking pins 310 for releasably coupling seal assembly 130 to outer housing 504. Seal assembly 130 and locking pins 310 are each as previously described.

Outer housing 504 of RCD 500 is substantially the same as outer housing 102 with the exception that outer housing 504 includes a pair of circumferentially-spaced annulus side outlets 506 that extend radially between inner surface 106 and outer surface 108 of housing 504. In this arrangement, side outlets 506 provide fluid communication between throughbore 104 of housing 504 and return conduits 502, which allow for the flow of fluid from wellbore 24 to the drilling vessel 12. An annular seal groove 508 and a plurality of circumferentially spaced apertures 510 are disposed about each side outlet 506. A flange at the end of one return conduit 502 is secured to housing 504 via bolts threaded into apertures 510 of each side outlet 506, and an annular seal is disposed in each seal groove 508 to seal between housing 504 and the flange bolted thereto.

Referring now to FIG. 12, another embodiment of a RCD 600 for use with either offshore system 10 shown in FIG. 1 or offshore system 400 shown in FIG. 10 (e.g., in place of RCD 100, 500) is shown. In this embodiment, RCD 600 has a central or longitudinal axis 605 and includes a generally cylindrical outer housing 602 and a plurality of circumferentially spaced actuation assemblies 610 coupled thereto. Outer housing 602 of RCD 600 includes an inner surface 604 defining a central throughbore 606 extending axially through outer housing 602. Shown schematically in FIG. 12, outer housing 602 may include features similar to those shown and described with respect to outer housing 102 of RCD 100 shown in FIGS. 2-5 and outer housing 502 of RCD 500 shown in FIG. 11. Actuation assemblies 610 of RCD 600 are configured to selectably lock or secure a seal assembly (not shown), such as seal assembly 130 shown in FIGS. 2-5 or the like, to outer housing 602.

In the embodiment of FIG. 12, each actuation assembly 610 of RCD 600 includes an actuatable locking pin 612 and a retaining arm 620 pivotally coupled to outer housing 602 at a pivot joint 622. The actuatable locking pin 612 of each actuation assembly 610 is disposed in a radially extending bore in outer housing 602 while retaining arm 620 is disposed in a recess disposed along the inner surface 604 of outer housing 602. The locking pin 612 of each actuation assembly 610 is configured to rotate or pivot its corresponding retaining arm 620 between a radially withdrawn or retracted unlocked position (shown in FIG. 12) and a radially advanced locked position. In the unlocked position, arm 620 is radially spaced from the seal assembly disposed within bore 606, however, in the locked position, a radially inner engagement surface 624 of the retaining arm 620 physically engages the outer surface of the seal assembly disposed within bore 606 to secure the seal assembly to outer housing 602. Particularly, locking pins 612 each include a generally cylindrical outer housing 614 and a sliding pin 616 slidably disposed within a central bore of outer housing 614. In certain embodiments, locking pins 612 are configured similarly to locking pins 310 shown in FIGS. 7-9. Thus, sliding pins 616 may be radially displaced within their respective outer housings 614 in response to hydraulic signals or pressures communicated to and from locking pins 612, where radial displacement of sliding pins 616 actuates corresponding retaining arms 620 between their unlocked and locked positions via physical engagement between a radially inner end of each sliding pin 616 and its corresponding retaining arm 620.

Referring now to FIG. 13, another embodiment of a RCD 630 for use with either offshore system 10 shown in FIG. 1 or offshore system 400 shown in FIG. 10 is shown (e.g., in place of RCD 100, 500). In this embodiment, RCD 630 has a central or longitudinal axis 635 and includes a generally cylindrical outer housing 632 and a plurality of circumferentially spaced actuation assemblies 640 coupled thereto. Outer housing 632 includes an inner surface 634 defining a central throughbore 636 extending axially through outer housing 632. Shown schematically in FIG. 13, outer housing 632 may include features similar to those shown and described with respect to outer housing 102 of RCD 100 shown in FIGS. 2-5 and outer housing 502 of RCD 500 shown in FIG. 11. Actuation assemblies 640 of RCD 630 are configured to selectably lock or secure a seal assembly, such as seal assembly 130 shown in FIGS. 2-5 or the like, to outer housing 632.

In the embodiment shown in FIG. 13, inner surface 634 of housing 632 includes an annular shoulder 638 extending radially inward therefrom. Annular shoulder 638 is configured to enage and physically support a seal assembly 650 disposed within bore 636 of outer housing 632. Seal assembly 650 has a first or upper end 650 a and a second or lower end 650 b, and includes a sealing member or boot 652 extending from lower end 650 b for sealing a rotating tubular member extending through bore 636. Shown schematically in FIG. 13, in certain embodiments the seal assembly 650 and sealing member 652 are configured similarly to seal assembly 130 and sealing member 210 shown in FIGS. 3-6 and described above. In this embodiment, each actuation assembly 640 includes a housing 642 extending radially through outer housing 632 and a locking pin 644 slidably disposed within the housing 642. In certain embodiments, locking pins 644 are configured similarly to locking pins 310 shown in FIGS. 7-9. Once seal assembly 650 has been received within bore 636 of outer housing 632 such that the lower end 650 b of seal assembly 650 is seated against annular shoulder 638, the locking pin 644 of each actuation assembly 640 may be actuated or displaced into a radially inner position (shown in FIG. 13) where a radially inner terminal end of each locking pin 644 is disposed directly adjacent or physically engages the upper end 650 a of seal assembly 650. In this arrangement, seal assembly 650 is axially locked into position between annular shoulder 638 and actuated locking pins 644. Locking pins 644 may be actuated into a radially outer position (not shown) to allow for relative movement of seal assembly 650 and outer housing 632 to allow for retrieval of seal assembly 650 therefrom.

Referring now to FIGS. 14 and 15, another embodiment of a RCD 660 for use with either offshore system 10 shown in FIG. 1 or offshore system 400 shown in FIG. 10 is shown (e.g., in place of RCD 100, 500). In this embodiment, RCD 660 has a central or longitudinal axis 665 and includes the outer housing 632 sown in FIG. 13 and a plurality of circumferentially spaced actuation assemblies 662 for selectably locking seal assembly 650 to outer housing 632. Particularly, each actuation assembly 662 includes a housing 664 extending radially through outer housing 632, a locking pin 666 extending through housing 664, a circumferentially extending retaining plate 668, and a connector 670 connecting the retaining plate 668 to a radially inner terminal end of the locking pin 666. In certain embodiments, locking pins 666 are configured similarly to locking pins 310 shown in FIGS. 7-9. The retaining plate 668 of each actuation assembly 662 extends partially along the circumference of the inner surface 634 of outer housing 632. As with actuation assemblies 640 discussed above with respect to FIG. 13, the locking pin 666 is actuatable between a radially withdrawn or retracted unlocked position (shown in FIG. 15) allowing for insertion or removal of seal assembly 650 from outer housing 632 and a radially advanced locked position (shown in FIG. 14) restricting relative axial movement between seal assembly 650 and outer housing 632. Particularly, in the radially inner position of locking pin 666, seal assembly 650 is axially locked between an axially lower end of each retaining plate 668 and the annular shoulder 638 of outer housing 632, where the circumferentially extending shape of each plate 668 provides additional physical support against the upper end 650 a of seal assembly 650. In certain embodiments, when the locking pins 666 are disposed in the radially outer position, retaining plates 668 are disposed in an annular groove (not shown) extending radially into inner surface 634. In other embodiments, retaining plates 668 may be allowed to extend into bore 636 when locking pins 666 are disposed in the radially outer position while still providing sufficient radial clearance for the insertion of seal assembly 650 therein.

Referring now to FIGS. 16-19, another embodiment of a RCD 680 for use with either offshore system 10 shown in FIG. 1 or offshore system 400 shown in FIG. 10 is shown (e.g., in place of RCD 100, 500). In this embodiment, RCD 680 has a central or longitudinal axis 685 and includes a generally cylindrical outer housing 682 and a plurality of circumferentially spaced actuation assemblies 700 coupled thereto. Outer housing 682 of RCD 680 includes an inner surface 684 defining a central throughbore 686 extending axially through outer housing 682. Shown schematically in FIGS. 16-19, outer housing 682 may include features similar to those shown and described with respect to outer housing 102 of RCD 100 shown in FIGS. 2-5 and outer housing 502 of RCD 500 shown in FIG. 11.

In the embodiment shown, outer housing 682 of RCD 680 includes an inner surface 684 defining a central throughbore 686 extending axially through outer housing 632. Inner surface 684 includes a plurality of circumferentially spaced locking lugs or flanges 688 extending radially inwards towards longitudinal axis 685. Each locking lug 688 is circumferentially aligned with a corresponding actuation assembly 690 disposed axially beneath and adjacent the locking lug 688. RCD 680 also includes a seal assembly 690 having a first or upper end 690 a and a second or lower end 690 b, and a sealing member 692 coupled to lower end 690 b for sealing against a rotating tubular member extending through bore 686 of outer housing 682. Shown schematically in FIGS. 16-19, in certain embodiments the seal assembly 690 and sealing member 692 are configured similarly to seal assembly 130 and sealing member 210 shown in FIGS. 3-6 and described above. In the embodiment shown, a generally cylindrical outer surface 694 of seal assembly 690 includes a plurality of circumferentially spaced locking lugs or flanges 696 extending radially outwards therefrom.

Locking lugs 696 are spaced along the circumference of the outer surface 694 of seal assembly 690 in a manner similar to the spacing of locking lugs 688 along the circumference of the inner surface 684 of outer housing 682. In this manner, seal assembly 690 includes an unlocked angular position (shown in FIGS. 16 and 17) where locking lugs 696 of seal assembly 690 do not circumferentially overlap with corresponding locking lugs 688 of outer housing 682, and a locked angular position (shown in FIGS. 18 and 19) where each locking lug 696 circumferentially aligns or overlaps with a corresponding locking lug 688. In this arrangement, seal assembly 690 is permitted to travel axially through bore 686 of outer housing 682 when disposed in the unlocked position, while relative axial movement is at least partially restricted between outer housing 682 and seal assembly 690 when seal assembly 690 is disposed in the locked position.

During installation of seal assembly 690 within outer housing 682, seal assembly 690 is lowered through bore 686 in the unlocked position until seal assembly 690 axially clears locking lugs 688. Once actuation assembly 700 has axially cleared locking lugs 688, seal assembly 690 is rotated into the locked position such that relative upward movement by seal assembly 690 within bore 686 is restricted via physical engagement of locking lugs 696, 688. In this position, seal assembly 690 is locked to outer housing 682 via actuating each of the plurality of actuation assemblies 700. Particularly, each actuation assembly 700 includes a housing 702 extending radially through outer housing 682 and a locking pin 704 disposed within housing 702. In certain embodiments, locking pins 706 are configured similarly to locking pins 310 shown in FIGS. 7-9. With seal assembly 690 disposed axially beneath locking lugs 688 and angularly in the locked position, the locking pin 704 of each actuation assembly 700 is actuated from a radially outer position (shown in FIGS. 16 and 17) to a radially inner position (shown in FIGS. 18 and 19) where a radially inner terminal end of each locking pin 704 is received within a corresponding aperture 698 extending radially into the outer surface 694 of each locking lug 696, thereby restricting axial and radial movement between seal assembly 690 and outer housing 682. In order to retrieve seal assembly 690 from outer housing 682, the locking pin 704 of each actuation assembly 700 may be retracted, and seal assembly 690 may be rotated into the unlocked position, thereby providing for relative axial movement between seal assembly 690 and outer housing 682.

Referring now to FIGS. 20 and 21, another embodiment of a RCD 710 for use with either offshore system 10 shown in FIG. 1 or offshore system 400 shown in FIG. 10 is shown (e.g., in place of RCD 100, 500). In this embodiment, RCD 710 has a central or longitudinal axis 715 and includes a generally cylindrical outer housing 712, a seal assembly 730 disposed therein, and a plurality of circumferentially spaced actuatable locking pins 310 for selectably locking seal assembly 730 to outer housing 712. Outer housing 712 includes a centrally disposed bore 714 extending between upper and lower ends of outer housing 712 and defined by a generally cylindrical inner surface 716. In the embodiment of FIGS. 20 and 21, inner surface 716 of outer housing 712 includes a first diameter section 716 a extending from the upper end of housing 712, a second diameter section 716 b extending from first section 716 a, a third diameter section 716 c extending from second section 716 b, and a fourth diameter section 716 d extending from third section 716 c, where first section 716 a is greater in diameter than second section 716 b, second section 716 b is greater in diameter than third section 716 c, and third section 716 c is greater in diameter than fourth section 716 d. A radially extending annular shoulder is formed between the intersection of each diameter section 716 a-716 d, including an annular landing profile 718 extending between third section 716 c and fourth section 716 d for engaging a corresponding landing shoulder of the seal assembly 730 to position seal assembly 730 within outer housing 712. In certain embodiments, when seal assembly 730 is landed within outer housing 712, a clearance remains between the annular shoulders formed between sections 716 a and 716 b, and 716 b and 716 c, and the corresponding annular shoulders of seal assembly 730.

In the embodiment shown in FIGS. 20 and 21, outer housing 712 also includes a first or upper radially extending lubrication passage 720 a and a second or lower radially extending lubrication passage 720 b axially spaced from upper passage 720 a, where passages 720 a and 720 b are configured to communicate a fluid to an internal chamber of seal assembly 730 for lubricating and/or controlling the temperature or pressure within the chamber of seal assembly 730. Outer housing 712 further includes a plurality of circumferentially spaced and radially extending apertures 722, where each aperture 722 receives an actuatable locking pin 310 for selectably locking seal assembly 730 to outer housing 712.

Seal assembly 730 includes features in common with seal assembly 130 described above, and shared features are labeled similarly. In the embodiment of FIGS. 20 and 21, seal assembly 730 generally includes an inner housing 732, bearing assembly 230, and a rotating sleeve assembly 750. Inner housing 732 includes a central bore 734 extending between upper and lower ends of inner housing 732 and defined by an inner surface 736, and a generally cylindrical outer surface 738 extending between the upper and lower ends of housing 732. In this embodiment, the outer surface 738 of inner housing 732 includes a radially extending annular shoulder 740 including a chamfered or angled landing profile for engaging the chamfered profile 360 of each locking pin 310 to secure seal assembly 730 to outer housing 712. The chamfered engagement between shoulder 740 and locking pins 310 provides an axial downward force against seal assembly 730 to pin seal assembly 730 against landing profile 718 of outer housing 712. The outer surface 738 of inner housing 732 also includes a first diameter section 738 a extending from annular shoulder 740, a second diameter section 738 b extending from first section 738 a, a third diameter section 738 c extending from second section 738 b, and a fourth diameter section 738 d extending from second section 738 c, where first section 738 a is greater in diameter than second section 738 b, second section 738 b is greater in diameter than third section 738 c, and third section 738 c is greater in diameter than fourth section 738 d. A radially extending annular shoulder is disposed at the intersection of each diameter section 738 a-738 d of outer surface 738, including a landing profile 739 disposed between third section 738 c and fourth section 738 d of outer surface 738 for matingly engaging the landing profile 718 of outer housing 712 to position seal assembly 730 within outer housing 712.

Inner housing 732 also includes a first or upper radially extending lubrication passage 742 a and a second or lower lubrication passage 742 b axially spaced from upper passage 742 a, where passages 742 a and 742 b are configured to receive fluid from passages 720 a and 720 b of outer housing 712 for lubricating components of bearing assembly 230. In this arrangement, when seal assembly 730 is seated within outer housing 712 as shown in FIGS. 20 and 21, upper passage 742 a of inner housing 732 is in fluid communication with upper passage 720 a of outer housing 712 and lower passage 742 b is in fluid communication with lower passage 720 b. Moreover, the inner surface 716 of outer housing 712 includes an annular grove extending therein at both upper passage 720 a and lower passage 720 b for providing fluid communication between passages 720 a/742 a and 720 b/742 b irrespective of the angular orientation between seal assembly 730 and outer housing 712. A first or upper set of annular seals 744 a are disposed along outer surface 738 adjacent upper passage 742 a and a second or lower set of annular seals 744 b are disposed along outer surface 738 adjacent lower passage 742 b such that upper seals 744 a seal the interface between passages 720 a/744 a and lower seals 744 b seal the interface between passages 720 b/744 b.

In the embodiment shown in FIGS. 20 and 21, rotating sleeve assembly 750 generally includes a rotating sleeve 752 rotatably coupled to inner housing 732 via bearing assembly 230 and a pair of sealing members or boots 210. Rotating sleeve 752 includes a first or upper end 752 a, a second or lower end 752 b, and a centrally disposed bore 754 extending between upper end 752 a and lower end 752 b. Bore 754 of rotating sleeve 752 has a first or upper diameter section 754 a extending from upper end 752 a and a second or lower diameter section 754 b extending from lower end 752 b, where upper section 754 a has a greater diameter than lower section 754 b for receiving the upper sealing member 210 therein. In addition, rotating sleeve includes a first or upper flange 756 a disposed at upper end 752 a for coupling sleeve 752 with the upper sealing member 210 and second or lower flange 756 b disposed at lower end 752 b for coupling sleeve 752 with lower the lower sealing member 210. In some embodiments, the outer diameter of upper flange 756 a is sized to be slightly less than the diameter of upper diameter section 716 a of outer housing 712 to limit angular offset between the longitudinal axis of outer housing 712 and the longitudinal axis of seal assembly 730 as seal assembly 730 is lowered into position within outer housing 712. In this manner, upper flange 756 a is configured to act as a stabilizer or centralizer to prevent seals 744 a, 744 b, and seal assembly 168 from inadvertently contacting or sliding against the inner surface 716 of outer housing 712 as seal assembly 730 is lowered through bore 714 of outer housing 712. However, a radial clearance is provided between the outer surface of upper flange 756 a and the inner surface 716 of outer housing 712 to prevent rotating sleeve 752 from contacting inner surface 716 once seal assembly 730 has been locked into position within outer housing 712 via locking pins 310. In certain embodiments, seal assembly 730 is lowered into position about a tubular or drill pipe extending through bore 714 of outer housing 712. In this embodiment, engagement between the upper seal member 210 and the drill pipe may further stabilize seal assembly 730 as it is lowered into position within outer housing 712.

In this embodiment, seal assembly 730 includes a first or upper rotary seal 760 a and a second or lower rotary seal 760 b axially spaced from upper seal 760 a, where seals 760 a and 760 b are each disposed along the inner surface 736 of inner housing 732 and sealingly engage the outer surface of rotary sleeve 752 to restrict fluid communication therebetween. In this arrangement, a sealed chamber 762 is formed between rotary seals 760 a and 760 b and disposed within inner housing 732. In this manner, fluid may be circulated through chamber 762 via pumping fluid into chamber 762 via upper passages 720 a and 742 a, and pumping fluid out of chamber 762 via corresponding lower passages 720 b and 742 b. In certain embodiments, the fluid circulated through chamber 762 lubricates bearing assembly 230, and manages the temperature and/or pressure within chamber 762 to extend the service life of bearing assembly 230. In some embodiments, bearing assembly 230 may include fins or other mechanisms for enhancing heat transfer between bearing assembly 230 and the fluid circulated through chamber 762. In some embodiments, the pressurization of chamber 762 via passages 720 a/742 a and 720 b/742 b may reduce a pressure differential across the seals of seal assembly 168 to increase the sealing integrity of bore 714. In this embodiment, seal assembly 730 also includes an additional rotary seal 764 that engages a radially extending flange 766 of rotating sleeve 752 for physically supporting sleeve 752 and reducing a moment on the upper end 752 a of rotating sleeve 752.

In the embodiment shown, second diameter section 716 b of inner surface 716 of the outer housing 712 has a greater axial length than third section 716 c and fourth section 716 d. Similarly, second diameter section 738 b of outer surface 738 of the inner housing 732 has a greater axial length than third section 738 c and fourth section 738 d. In some embodiments, the diameter of first diameter section 738 a is slightly less than the diameter of first section 716 a, the diameter of second section 738 b is slightly less than the diameter of second section 716 b, the diameter of third section 738 b is slightly less than the diameter of third section 716 c, and the diameter of fourth section 738 b is slightly less than the diameter of fourth section 716 d. In this arrangement, upper seals 744 a may sealingly engage the second section 716 b of inner surface 716, lower seals 744 b may sealingly engage the third section 716 c, and the seals of seal assembly 168 may sealingly engage the fourth section 716 d. In some embodiments, the gradual alteration of diameter of inner surface 716 and outer surface 738 increases the radial clearance between seals 744 a, 744 b, and 168 and inner surface 716 of outer housing 712 as the seal assembly 730 is lowered into position to reduce the possibility of damaging those seals during that process. Particularly, given the relatively short axial length of diameter sections 716 c and 716 d relative section 716 a, lower seals 744 b and the seal of assembly 168 only slidingly engage sections 716 c and 716 d of inner surface 716 for a relatively short axial distance as seal assembly 730 is lowered into position within outer housing 712, thereby preserving and protecting seals 144 b and 168. Moreover, upper seals 744 a are disposed at an upper end of second diameter section 738 b of outer surface 738 such that seals 744 a only slidingly engage a relatively small portion of the overall axial length of second section 716 b as seal assembly 730 is installed within outer housing 712, thereby protecting and preserving upper seals 744 a. In some embodiments, the edges of the annular grooves in fluid communication with passages 720 a and 720 b of outer housing 712 are radiused to mitigate the possibility of damaging seals 744 a, 744 b, and 168 as seal assembly 730 is installed within outer housing 712.

Referring now to FIGS. 22-25, another embodiment of a RCD 800 for use with offshore system 10 of FIG. 1 is shown (e.g., in place of RCD 100). Thus, in the embodiment shown in FIGS. 22-25, RCD 800 comprises a below-tension-ring (BTR) RCD that is located beneath tension ring 40 shown in FIG. 1. Although in this embodiment RCD 800 is configured for use with offshore system 10 of FIG. 1, in other embodiments, RCD 800 may be used with the offshore system 400 shown in FIG. 10, and thus, may comprise an above-tension-ring (ATR) RCD located above tension ring 40. In the embodiment shown in FIGS. 22-25, RCD 800 has a central or longitudinal axis 805 and includes a generally cylindrical outer housing 802, a seal assembly 850 disposed therein, and a plurality of circumferentially spaced actuatable locking pins 840 for selectably locking seal assembly 850 to outer housing 802. Outer housing 802 of RCD 800 has a first or upper end 802 a, a second or lower end 802 b, a central throughbore or passage 804 extending between ends 802 a, 802 b, and defined by a generally cylindrical inner surface 806, and a generally cylindrical outer surface 808 extending between ends 802 a and 802 b .

In the embodiment shown in FIGS. 22-25, outer housing 802 of RCD 800 includes a plurality of circumferentially spaced side outlet ports 810 (shown in FIG. 23) each extending radially between inner surface 806 and outer surface 808. Outlet ports 810 are similar in configuration and function as the side outlets 506 of the RCD 500 shown in FIG. 11. In the embodiment shown in FIGS. 22-25, RCD 800 includes at least one side outlet housing 812 mounted to the outer surface 808 of outer housing 802, where side outlet 812 includes a bore or passage 814 extending therein that is in fluid communication with at least one of the outlet ports 810 of outer housing 802. Side outlet 816 includes a connector 816, such as a flanged connector, for releasably coupling with a corresponding connector of a return conduit (e.g., return conduit 502 shown in FIG. 10) of offshore system 400.

Outer housing 802 includes an umbilical stab plate or panel 818 secured to the outer surface 808 thereof. Stab plate 818 includes electrical and fluid connections for establishing signal communication with various components of RCD 800 as will be described in more detail below. Stab plate 818 can be accessed prior to installation of RCD 800. For instance, electrical and fluid connections may be made up with stab plate 818 prior to installation of RCD 800. Alternatively, stab plate 818 may be accessed by a remotely operated underwater vehicle (ROV) to connect and disconnect signal conduits or umbilicals to the various connectors coupled with stab plate 818. In the embodiment shown in FIGS. 22-25, stab plate 818 is coupled with or secures a first electrical connector 820 a, a second electrical connector 820 b, a first or inlet lubricant connector 822 a, a second or outlet lubricant connector 822 b, a first or locking connector 824 a, and a second or unlocking connector 824 b.

Each electrical connector 820 a and 820 b connects a plurality of electrical cables 826 extending to various electrical components of RCD 800. In some embodiments, prior to installing RCD 800 in offshore system 10, electrical cables or conduits in signal communication with a control or monitoring system 75 of the offshore system 10 are connected to electrical connectors 820 a and 820 b to provide signal communication between electrical connectors 820 a and 820 b. In other embodiments, an ROV may be used to connect the electrical cables of monitoring system 75 with electrical connectors 820 a and 820 b following installation of RCD 800 in offshore system 10.

In the embodiment shown in FIGS. 22-25, outer housing 802 includes a bore pressure and temperature sensor 830 coupled with housing 802, where bore sensor 830 is in signal communication with first electrical connector 820 a via an electrical cable 826 extending therebetween. Bore sensor 830 is configured to monitor the pressure and temperature of fluid disposed in the bore 804 of outer housing 802, where the pressure and temperature measurements provided by bore sensor 830 may be communicated in real-time to system 75 of offshore system 10 via the electrical connection provided by first electrical connector 420. Although in the embodiment shown in FIGS. 22-25 bore sensor 830 comprises a pressure and temperature sensor, in other embodiments, bore sensor 830 may be configured to measure various properties of fluid disposed in the bore 804 of outer housing 802, such as fluid flow, fluid content, etc.

In the embodiment shown in FIGS. 22-25, the outer housing 802 of RCD 800 also includes a first or inlet lubrication passage 828 a and a second or return lubrication passage 828 b (shown in FIG. 25), with passages 828 a and 828 b each extending radially between the inner surface 806 and outer surface 808 of outer housing 802. Similar to the functionality provided by passages 720 a and 720 b of RCD 710 shown in FIGS. 20 and 21, passages 828 a and 828 b of the outer housing 802 of RCD 800 are configured to communicate a fluid to an internal chamber of seal assembly 850 for lubricating and/or controlling the temperature or pressure within the chamber of seal assembly 850. In the embodiment shown in FIGS. 22-25, a first fluid conduit 832 a extends between inlet lubricant connector 822 a and inlet lubrication passage 828 a to provide fluid communication therebetween while a second fluid conduit 832 b extends between return lubricant connector 822 b and return lubricant passage 828 b to provide fluid communication therebetween. In some embodiments, prior to installing RCD 800 in offshore system 10, fluid conduits in fluid communication with an RCD lubrication system 77 of offshore system 10 may be connected with lubricant connectors 822 a and 822 b of RCD 800 to establish a lubrication loop configured to provide continuous circulation of lubricant through the seal assembly of 850 of RCD 800. In other embodiments, the fluid conduits of lubrication system 77 may be connected to lubricant connectors 822 a and 822 b following the installation of RCD 800 in offshore system 10, such as via an ROV or personnel of offshore system 10.

In the embodiment shown in FIGS. 22-25, a temperature and pressure sensor 832 is coupled to the lower fluid conduit 832 b to measure the pressure and temperature of lubricating fluids circulating between the return lubricant passage 828 b of outer housing 802 and return lubricant connector 822 b. An electrical cable 826 extends between lubricant temperature and pressure sensor 832 and the first electrical connector 820 a to place electrical connector 820 a in signal communication with lubricant sensor 832. Either before or after the installation of RCD 800 in offshore system 10, an electrical conduit of lubrication system 77 of offshore system 10 may be connected to, or otherwise placed in signal communication with, first electrical connector 820 a of RCD 800 such that lubrication sensor 832 may provide real-time pressure and temperature measurements of lubricating fluid circulated through seal assembly 850 to lubrication system 77. Although in the embodiment shown in FIGS. 22-25 lubrication sensor 832 comprises a pressure and temperature sensor, in other embodiments, lubrication sensor 832 may be configured to measure various properties of fluid flowing through the lower fluid conduit 832 b of outer housing 802, such as fluid flow, fluid content, etc. In some embodiments, lubrication system 77 of the offshore system 10 may include a hydraulic power unit (HPU) for circulating lubricating fluids through lubrication system 77, where the HPU may include a level sensor for monitoring the level of lubricating fluid therein to detect leakage of the lubricating fluid from the closed circuit or lubrication loop formed in lubrication system 77.

Locking pins 840 of the RCD 800 are similar to locking pins 310 shown in FIGS. 7-9, and shared features are labeled similarly. In the embodiment shown in FIGS. 22-25, each locking pin 840 includes an outer housing 842 and a sliding pin 844 slidably disposed in the outer housing 842. Unlike the sliding pin 350 of locking pin 310, an outer surface of sliding pin 844 does not include a cammed profile, and instead, includes a locking shoulder 846 configured to matingly engage a corresponding locking shoulder of seal assembly 850 to secure seal assembly 850 to outer housing 802. Additionally, unlike locking pins 310 described above, each locking pin 840 includes a position sensor 848 that extends into and couples with the sliding pin 844 of each locking pin 840. Also unlike locking pins 310, the locking shoulder 846 of each sliding pin 844 extends orthogonal the central axis of outer housig 802 (i.e., central axis 805) of RCD 800.

The position sensor 848 of each locking pin 840 is configured to measure an axial position of the sliding pin 844 of the locking pin 840. Particularly, position sensor 848 is configured to measure whether the sliding pin 844 of the locking pin 840 is disposed in a radially outer unlocked position, where relative axial movement between seal assembly 850 and outer housing 802 is permitted, and a radially inner locked position (shown in FIG. 24), where relative axial movement between seal assembly 850 and outer housing 802 is restricted. Each position sensor 848 is connected to an electrical cable 826 extending between the sensor 848 and one of the electrical connectors 820 a and 820 b of RCD 800. In this manner, the position of the sliding pins 844 of locking pins 840 may be communicated to monitoring system 75 via the electrical connection provided by electrical connectors 820 a and 820 b with monitoring system 75. Thus, position sensors 848 are configured to provide confirmation as to the position of sliding pins 848 of locking pins 840. In the embodiment shown in FIGS. 22-25, position sensors 848 comprise linear variable differential transformer (LVDT) sensors; however, in other embodiments, position sensors 848 may comprise other sensors known in the art for measuring position, such as magnetic proximity sensors.

As mentioned above, the stab plate 818 of RCD 800 includes locking connector 824 a and unlocking connector 824 b. In the embodiment shown in FIGS. 22-25, outer housing 802 of RCD 800 includes fluid conduits 834 that provide fluid communication between locking connector 824 a and the closing passage 368 of each locking pin 840, and between unlocking connector 824 b and the opening passage 366 of each locking pin 840. Either before or after installation of RCD 800 in the offshore system 10 shown in FIG. 1, fluid conduits of control and monitoring system 75 of offshore system 10 may be connected to the locking connector 824 a and unlocking connector 824 b of RCD 800 to allow system 75 to control the locking and unlocking of locking pins 840 of RCD 800. In this arrangement, the locking and unlocking of the locking pins 840 of RCD 800 may be controlled remotely at the drilling vessel 12 via control and monitoring system 75.

In the embodiment shown in FIGS. 22-25, the outer housing 802 of RCD 800 additionally includes a first or upper proximity sensor 836 a and a second or lower proximity sensor 836 b (shown in FIG. 24), where both upper proximity sensor 836 a and lower proximity sensor 836 b each extend into the bore 804 of outer housing 802. As will be discussed further herein, proximity sensors 836 a and 836 b are each configured to output a proximity or position signal in response to the positioning of a sensor element within the proximity of sensors 836 a and 836 b. Each proximity sensor 836 a and 836 b is connected to an electrical cable 826 extending between proximity sensors 836 a and 836 b and the second electrical connector 820 b of RCD 800. In this configuration, the position or proximity signals outputted by proximity sensors 836 a and 836 b may be communicated in real-time to the monitoring system 75 of the offshore system 10 shown in FIG. 1.

Seal assembly 850 of RCD 800 includes features in common with the seal assembly 730 of RCD 710 shown in FIGS. 20 and 21 and the seal assembly 130 of RCD 100 shown in FIGS. 3-6, and shared features are labeled similarly. In the embodiment shown in FIGS. 22-25, seal assembly 850 generally includes an inner housing 852, bearing assembly 230, and a rotating sleeve assembly 870. Inner housing 852 includes a central bore or bearing chamber 854 extending between upper and lower ends of inner housing 852 and defined by an inner surface 856, and a generally cylindrical outer surface 858 extending between the upper and lower ends of housing 852. In this embodiment, the outer surface 858 of inner housing 852 includes a radially extending annular shoulder 860 configured to matingly engage the locking shoulder 846 of the sliding pin 844 of each locking pin 840 when sliding pins 844 are disposed in the radially inner locked position.

In this embodiment, inner housing 852 of seal assembly 850 includes a first or upper radially extending lubrication passage 862 a and a second or lower lubrication passage 862 b (shown in FIG. 25) axially spaced from upper passage 862 a, where lubrication passages 862 a and 862 extend between the inner and outer surfaces 856 and 858, respectively, of inner housing 852. Lubrication passages 862 a and 862 b are in fluid communication with lubrication passages 828 a and 828 b, respectively, of outer housing 802. In this configuration, lubricating fluids or lubricant may be pumped or flowed into bearing chamber 854 of inner housing 852 via lubrication passages 828 a and 862 a and out of bearing chamber 854 via lubrication passages 862 b and 828 b to thereby circulate lubricating fluids to the bearing assembly 230 disposed in bearing chamber 854 of inner housing 852.

To prevent or mitigate loss of lubricating fluids during operation of RCD 800, RCD 800 includes a first pair of check valves 863 a and 863 b positioned in lubrication passages 828 a and 828 b, respectively, of outer housing 802, and a second pair of check valves 865 a and 865 b positioned in passages 862 a and 862 b, respectively, of inner housing 852. Particularly, the first or upper check valve 863 a positioned in the inlet lubrication passage 828 a of outer housing 828 b is configured to prevent fluid flow from passage 828 a into the first fluid conduit 832 a while the second or lower check valve 863 b positioned in the return lubrication passage 828 b of outer housing 802 is configured to prevent fluid flow from second fluid conduit 832 b into the return conduit 828 b. Additionally, the first or upper check valve 865 a positioned in the upper lubrication passage 862 a of inner housing 852 is configured to restrict fluid flow from bearing chamber 854 into passage 862 a, while the second or lower check valve 865 b positioned in the lower lubrication passage 862 b of inner housing 852 is configured to restrict fluid flow from lower lubrication passage 828 b into bearing chamber 854. In the embodiment shown in FIGS. 22-25, annular seals disposed along the outer surface 856 of inner housing 852 seal the fluid connection formed between inlet lubrication passage 828 a and the upper lubrication passage 862 a and the fluid connection formed between return lubrication passage 828 b and lower lubrication passage 862 b.

Rotating sleeve assembly 870 of the seal assembly 850 of RCD 800 generally includes a rotating sleeve 872 rotatably coupled to inner housing 852 via bearing assembly 230 and a pair of sealing members or boots 210 (shown as 210 a and 210 b in FIGS. 22-25) coupled to rotating sleeve 872. Rotating sleeve 872 includes a central bore or passage 874 defined by a generally cylindrical inner surface 876, and a generally cylindrical outer surface 878. A first or upper boot 210 a is coupled to sleeve 872 proximal an upper end of sleeve 872 while a second or lower boot 210 b is coupled to a lower end of sleeve 872.

Referring now to FIGS. 22-26, the outer surface 878 of sleeve 872 includes a first or upper proximity sensor element 880 a and a second or lower sensor element 880 b axially spaced from upper sensor element 880 a (shown in FIGS. 24 and 26). Upper sensor element 880 a comprises a magnetic member 880 a and is axially aligned with upper proximity sensor 836 a when seal assembly 850 is landed in the outer housing 802 of RCD 800. Particularly, upper proximity sensor 836 a is configured to output a position or proximity signal when upper sensor element 880 a is substantially circumferentially aligned with upper proximity sensor 836 a. Thus, proximity sensor 836 a is configured to detect the proximity of the magnetic member or upper sensor element 880 a.

In this arrangement, upper proximity sensor 836 a comprises a revolutions per minute (RPM) or rotational speed sensor of rotating sleeve 872. Specifically, when sleeve 872 rotates relative outer housing 802 during operation of RCD 800, upper proximity sensor 836 a will output a position signal each time upper sensor element 880 a rotates past sensor 836 a. In this manner, the frequency of position signals outputted by upper proximity sensor 836 a correlates with the rotational speed of rotating sleeve 872, where faster rotation of sleeve 872 translates to more rotations of upper sensor element 880 a past upper proximity sensor 836 a over a given period of time. Thus, in the embodiment shown in FIGS. 22-26, the combination of upper proximity sensor 836 a and upper sensor element 880 a form a rotational speed sensor 882.

In the embodiment shown in FIGS. 22-26, lower sensor element 880 b of rotating sleeve 872 comprises a sensor element assembly 880 b that includes a housing 884, a piston 886 slidably disposed in the housing 884, a magnetic member or sensor element 888, and a biasing member 890, a burst disc 892 (shown in FIG. 26). Magnetic member 888 is coupled to a radially outer end of piston 886. Biasing member 890 is disposed about piston 886 and is configured to bias piston 886 into a radially inwards position (shown in FIG. 26) towards the central axis 805 of RCD 800. Burst disc 892 is coupled to a radially inner end of housing 884. In the embodiment shown in FIGS. 22-26, the inner surface 876 of rotating sleeve 872 includes a passage 879 extending radially therein that receives sensor element assembly 880 b. Positioned in passage 879, burst disc 892 restricts fluid communication between the bore 874 of sleeve 872 and the radially inner end of piston 886.

In the embodiment shown in FIGS. 22-26, burst disc 892 of sensor element assembly 880 b is configured to burst or rupture in response to the application of a predetermined fluid pressure to burst disc 892, where rupturing of burst disc 892 provides fluid communication between the radially inner end of piston 886 and the bore 874 of rotating sleeve 872. Additionally, biasing member 890 of sensor element assembly 880 b is configured to retain piston 886 in the radially inner position as sleeve 872 rotates within the outer housing 802 of RCD during the operation of RCD 800. In other words, biasing member 890 biases against or counteracts the radially outwards directed centripetal force applied to piston 886 during rotation of sleeve 872. In the event that a leak occurs between the lower boot 210 b and an outer surface of the drillstring 18 (shown in FIG. 1) extending through RCD 800, then fluid pressure in the bore 874, and particularly in the annulus 875 formed between the inner surface 876 of sleeve 872 and the outer surface of drillstring 18, will increase as fluid pressure is communicated between the bore 804 of outer housing 802 and annulus 875. Piston 886 is configured to actuate or be displaced from the radially inner position into a radially outer position in response to the communication of fluid pressure from annulus 875 to the radially inner end of piston 886 following the rupturing of burst disc 892.

In response to the increase in fluid pressure in annulus 875, burst disc 892 is configured to rupture to allow the fluid pressure in annulus 875 to be communicated to the radially inner end of piston 886. In the radially outer position, the lower proximity sensor 836 b, which is axially aligned with sensor element assembly 880 b when seal assembly 850 is landed in outer housing 802, is configured to output a position or proximity signal when piston 886 and the magnetic member 888 coupled thereto are substantially circumferentially aligned with sensor 836 b. Thus, similar to the functionality of upper proximity sensor 836 a and sensor element 880 a, lower proximity sensor 836 b will output a position or proximity signal each time piston 886 rotates past sensor 836 b when piston 886 is disposed in the radially outer position, where the position sensor outputted by lower proximity sensor 836 b may be communicated to control and monitoring system 75 of offshore system 10 via the second electrical connector 820 b. In this configuration, the combination of lower proximity sensor 836 b and sensor element assembly 880 b forms a leak sensor 894 configured to detect leakage between the lower boot 210 b and the outer surface of drillstring 18 during the operation of RCD 800. In some embodiments, the leakage detection functionality provided by leak sensor 894 may be used to determine when seal assembly 850 should be pulled out or removed from the outer housing 802 of RCD 800 to allow lower boot 210 b to be replaced, eliminating unnecessary maintenance to seal assembly 850 while allowing seal assembly 850 to be repaired before both upper and lower boots 210 a and 210 b, respectively, are permitted to leak through wear occurring during the operation of RCD 800. For instance, given that lower boot 210 b is exposed to the pressure of fluid disposed in the lower end of central bore 804 of outer housing 802 (i.e., the section of bore 804 extending between the sealing engagement between seal assembly 850 and inner surface 806 and the lower end 802 b of outer housing 802), in some applications lower boot 210 b may be exposed to a harsher operating environment and may be required to seal across a higher differential pressure than upper boot 210 a, causing lower boot 210 b to fail before upper boot 210 a. In such applications, by removing and repairing or replacing seal assembly 850 following the detection of leakage across lower boot 210 b, seal assembly 850 may be repaired or replaced before leakage results across both upper boot 210 a and lower boot 210 b.

In the embodiment shown in FIGS. 22-25, RCD 800 further includes a sleeve sensor assembly 868 (shown in FIG. 24) generally comprising a sleeve pressure and temperature transducer 869 a and an outer housing transmitter 869 b in signal communication with sleeve transducer 869 a. Sleeve transducer 869 a is disposed in a receptacle formed in rotating sleeve 872 and is in fluid communication with central bore 874 of sleeve 872. Outer housing transmitter 869 b is disposed along the inner surface 806 of outer housing 802 and is connected to one of the electrical connectors 820 a or 820 b via an electrical cable 826 (not shown in FIG. 24). In the embodiment shown in FIGS. 22-25, sleeve transducer 869 a of sleeve sensor assembly 868 is battery powered and configured to measure pressure and temperature of fluid disposed in the central bore 874 of rotating sleeve 872, and particularly the pressure and temperature of fluid disposed in annulus 875 when drillstring 18 is disposed in bore 874. In other embodiments, sleeve transducer 869 a may be configured to measure various properties of fluid disposed in central bore 874 of rotating sleeve 872, such as fluid flow, fluid content, etc.

Sleeve transducer 869 a of sleeve sensor assembly 868 is additionally configured to wirelessly transmit sensors signal indicative of the measured pressures and temperatures of fluid in bore 874 to outer housing transmitter 869 b, where outer transmitter 869 b is configured to receive said sensor signals and transmit them to one of the electrical connectors 820 a or 820 b of RCD 800. In this configuration, sleeve sensor assembly 860 is configured to indicate pressure and temperature of fluid disposed in central bore 874 of rotating sleeve 872 in real-time. Additionally, the wireless communication between sleeve transducer 869 a and outer housing transmitter 869 b allows transducer 869 a to communicate signals indicative of pressure and temperature of fluid in bore 874 of sleeve 872 as sleeve 872 rotates relative outer housing 802. Further, increases in fluid pressure in central bore 874 of rotating sleeve 872 may indicate leakage of fluid past lower boot 210 b, allowing an operator of RCD 800 to repair or replace seal assembly 850 before a leak is formed in both boots 210 a and 210 b. While RCD 800 is shown in the embodiment of FIG. 22-25 as including sleeve sensor assembly 868, in other embodiments, RCD 800 may not include sleeve sensor assembly 868.Referring now to FIGS. 22-25 and 27, an embodiment of a protective sleeve 900 for landing in the outer housing 802 of RCD 800 is shown in FIG. 27. Sleeve 900 is configured to be inserted into and locked (via locking pins 840) within outer housing 802 to protect features of RCD 800 from fluid or tools displaced through bore 804 of outer housing 802 when seal assembly 850 is not needed for the operation of offshore system 10, such as when offshore system 10 is not engaged in managed pressure drilling (MPD). Particularly, sleeve 900 is configured to protect landing profiles or shoulders formed in the inner surface 806 of outer housing 802, including the shoulder seal assembly 850 lands against, as well as electronic components of RCD 800, such as the radially inner ends of proximity sensors 836 a and 836 b.

In the embodiment shown in FIGS. 22-25 and 27, protective sleeve 900 is generally cylindrical in shape and includes a central bore or passage 902 defined by a generally cylindrical inner surface 904 extending between upper and lower ends of sleeve 900, and a generally cylindrical outer surface 906 extending between the upper and lower ends of sleeve 900. The outer surface includes a plurality of annular seals disposed therein for restricting fluid communication across the annulus formed between the outer surface 906 of sleeve 900 and the inner surface 806 of outer housing 802 to thereby protect the above described features of inner surface 806 and RCD 800. Additionally, the outer surface 906 of sleeve 900 includes an annular shoulder 908 formed therein for matingly engaging the locking shoulders 846 of the sliding pins 844 of locking pins 840 to selectively lock sleeve 900 to outer housing 802. Particularly, following the landing of sleeve 900 in outer housing 802, sliding pins 844 of locking pins 840 may be actuated into the radially inner locked position to engage shoulder 908 and thereby lock sleeve 900 and to outer housing 802.

In the manner described, embodiments described herein (e.g., systems 10 and/or 100) include RCDs (e.g., RCDs 100, 500, 600, 630, 660, 680, 710, and/or 800) comprising an outer housing (e.g., outer housings 102, 504, 602, 632, 682, 712, and/or 802) and a seal assembly (e.g., seal assemblies 130, 650, 690, 730, and/or 850) receivable within the outer housing and configured to seal against an outer surface of a tubular member (e.g., drillstring 18) extending therethrough while, at the same time, allowing for relative rotation between the tubular member and the outer housing. Additionally, embodiments of RCDs described herein include locking pins (e.g., locking pins 310, 612, 644, 666, 706, and/or 840) actuatable between a radially outer unlocked position permitting relative axial movement between the seal assembly and outer housing of the RCD, and a radially inner locked position restricting relative axial movement between the seal assembly and the outer housing, in response to the application of fluid pressure thereto. Embodiments of locking pins described herein advantageously allow the seal assembly of the RCD to be locked and unlocked remotely via communicating fluid pressure to the locking pins.

Additionally, embodiments of locking pins described herein provide the advantage of not intruding into a central bore of the outer housing when disposed in the unlocked position (i.e., the radially inner terminal end of each locking pin is flush with or recessed within the inner surface of the outer housing when in the unlocked position), thereby allowing full bore access to the outer housing of the RCD when the seal assembly is not received therein. Further, embodiments of locking pins described herein provide a secure axial locking of the seal assembly of the RCD to the outer housing thereof by physically engaging a surface or shoulder of the seal assembly with a mating surface or shoulder of each locking pin when the locking pins are disposed in the radially inner positions. Embodiments of locking pins described herein are also accessible from the outside of the RCD, being disposed in the outer housing thereof, such that hydraulic, electrical, or other connections may be conveniently provided and accessed from the exterior of the RCD.

Embodiments of RCDs described herein also include the feature of a lubrication system (e.g., lubrication system 77) for providing a closed lubrication loop or circuit extending from an exterior of the RCD to a bearing assembly (e.g., bearing assembly 230) of the RCD. Embodiments of lubrication systems described herein are configured to provide a continuous circulation of lubricant to a bearing assembly of the RCD. By providing continuous circulation of lubricant from an exterior of the RCD to the bearing assembly disposed therein, the lubricant may be conditioned (e.g., pressure and/or temperature controlled, filtered, etc.) and fluid properties of the lubricant (e.g., pressure, temperature, etc.) may be monitored in real-time. Additionally, the amount of lubricant in the lubrication system may be monitored to determine the presence of any leaks therein. Further, embodiments of lubrication systems described herein include mechanisms (e.g., check valves 863 a/863 b and 865 a/865 b) configured to prevent leakage or reverse flow through the lubrication system.

Embodiments of RCDs described herein further include sensor assemblies (e.g., sensors 830, 832, 848, 868, 882, and/or 894) and associated components (e.g., stab plate 818) configured to measure properties of the RCD and transmit sensor signals indicative of those measured properties in real-time to a rig or platform of the system in which the RCD is used. For instance, embodiments of RCDs described herein include sensors configured to provide pressure and temperature measurements of the bore of the outer housing of the RCD, pressure and temperature measurements of a bore of a rotating sleeve of the seal assembly of the RCD, pressure and temperature sensors for the lubrication system of the RCD, position sensors for the locking pins of the RCD, rotational speed or RPM sensors for measuring rotational speed of the rotating sleeve, and leak sensors configured to detect the presence of a leak in one of the sealing elements of the sealing element of the RCD. Using the embodiments of sensors described herein, operation and performance of the RCD may be monitored, thereby allowing for safer operation of the RCD and the ability to repair or maintain the RCD prior to failure thereof (e.g., leakage past each sealing element of the RCD, etc.) in response to failure or leak detections made by the sensors.

While disclosed embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the disclosure. For example, the relative dimensions of various parts, the materials from which the various parts are made, and other parameters can be varied. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps. 

What is claimed is:
 1. A rotating control device for sealing an annulus extending from a subterranean wellbore, the rotating control device comprising: an outer housing including a central axis, a first end, a second end opposite the first end, an outer surface extending axially from the first end to the second end, and an inner surface extending axially from the first end to the second end, wherein the inner surface defines a throughbore extending axially through the outer housing, and wherein the outer housing comprises a plurality of circumferentially-spaced bores extending radially from the outer surface to the throughbore; a seal assembly disposed within the outer housing and configured to seal against a rotating tubular member extending axially through the throughbore of the outer housing, wherein the seal assembly comprises an outer surface including a receptacle; and a plurality of actuatable locking pins, wherein each locking pin is moveably disposed in one of the bores of the outer housing and is configured to move radially relative to the outer housing between a locked position with a radially inner end the locking pin seated in the receptacle and an unlocked position with the radially inner end of the locking pin removed from the receptacle.
 2. The rotating control device of claim 1, wherein the inner surface of the outer housing comprises an annular shoulder configured to engage a mating annular shoulder on the outer surface of the seal assembly.
 3. The rotating control device of claim 2, wherein the annular shoulder of the outer housing comprises a frustoconical surface configured to slidingly engage a mating frustoconical surface of the annular shoulder of the seal assembly.
 4. The rotating control device of claim 2, wherein the radially inner end of each locking pin comprises a chamfered profile configured to engage a corresponding chamfered profile of the outer surface of the seal assembly and urge the annular shoulder of the seal assembly in engagement with the annular shoulder of the outer housing.
 5. The rotating control device of claim 1, wherein each locking pin comprises a fluid passage configured to be pressurized to transition the locking pin between the unlocked position and the locked position.
 6. The rotating control device of claim 1, further comprising a position sensor disposed in one of the locking pins, wherein the position sensor is configured to output a signal indicating the position of the locking pin in the locked position or the unlocked position.
 7. The rotating control device of claim 6, further comprising a stab plate coupled to the outer surface of the outer housing, wherein the stab plate comprises: a first fluid connector in fluid communication with a first fluid conduit; a second fluid connector in fluid communication with a second fluid conduit; and an electrical connector in signal communication with the position sensor; wherein at least one of the locking pins is configured to transition from the unlocked position to the locked position in response to pressurization of the first fluid conduit; wherein at least one of the locking pins is configured to transition from the locked position to the unlocked position in response to pressurization of the second fluid conduit.
 8. The rotating control device of claim 2, wherein the radially inner end of each locking pin comprises a shoulder extending orthogonal the central axis of the outer housing.
 9. The rotating control device of claim 1, wherein: the outer housing includes a first passage extending from the inner surface to the outer surface and a second passage extending from the inner surface to the outer surface; the seal assembly comprises an inner housing including a first passage extending from an inner surface to an outer surface of the inner housing and a second passage extending from the inner surface to the outer surface of the inner housing; the first passage of the outer housing is in fluid communication with the first passage of the inner housing, and wherein the first passage of the outer housing and the first passage of the inner housing are configured to supply a lubricating fluid to a bearing chamber of the inner housing; and the second passage of the outer housing is in fluid communication with the second passage of the inner housing, and wherein the second passage of the outer housing and the second passage of the inner housing are configured to receive the lubricating fluid from the bearing chamber.
 10. The rotating control device of claim 9, wherein: the first and second passages of the outer housing each include a check valve; and the first and second passages of the inner housing each include a check valve.
 11. The rotating control device of claim 1, further comprising: a first proximity sensor disposed along the inner surface of the outer housing; and a first sensor element disposed along an outer surface of an inner housing of the seal assembly; wherein the first proximity sensor is configured to measure the rotational speed of the seal assembly in response to rotation of the seal assembly in the outer housing.
 12. The rotating control device of claim 11, further comprising: a second proximity sensor disposed along the inner surface of the housing; and a second sensor element disposed along the outer surface of the inner housing; wherein the second sensor element is configured to detect a leak in a sealing element of the seal assembly in response to leakage across the sealing element.
 13. A rotating control device for sealing an annulus extending from a subterranean wellbore, the rotating control device comprising: an outer housing including a central axis, a first end, a second end opposite the first end, an outer surface extending axially from the first end to the second end, and an inner surface extending axially from the first end to the second end, wherein the inner surface defines a throughbore extending axially through the outer housing, and wherein the outer housing comprises a plurality of circumferentially-spaced bores extending radially from the outer surface to the throughbore; a plurality of actuatable locking pins, wherein each locking pin is moveably disposed in one of the bores of the outer housing and is configured to move radially relative to the outer housing between a locked position with a radially inner end the locking pin seated in the receptacle and an unlocked position with the radially inner end of the locking pin removed from the receptacle.
 14. The rotating control device of claim 13, further comprising: a seal assembly configured to be removably disposed within the outer housing, wherein the seal assembly comprises an outer surface including a receptacle configured to receive a radially inner end of each locking pin of the outer housing.
 15. The rotating control device of claim 14, wherein the seal assembly has a first position seated within the throughbore of the outer housing and a second position removed from the throughbore of the outer housing.
 16. The rotating control device of claim 15, wherein the seal assembly is configured to be lowered into the throughbore of the outer housing at the first end of the outer housing.
 17. The rotating control device of claim 14, wherein the inner surface of the outer housing comprises an annular shoulder and the outer surface of the seal assembly comprises an annular shoulder configured to axially abut the annular shoulder of the outer housing in the first position.
 18. The rotating control device of claim 14, wherein each locking pin comprises a fluid passage configured to be pressurized to transition the locking pin between the unlocked position and the locked position.
 19. The rotating control device of claim 18, wherein each locking pin comprises a position sensor configured to indicate the position of the locking pin in the locked position or the unlocked position.
 20. A rotating control device for sealing an annulus extending from a subterranean wellbore, comprising: an outer housing including a central axis, a first end, a second end opposite the first end, an inner surface extending axially from the first end to the second end, and an outer surface extending between the first end and the second end, wherein the inner surface defines a throughbore extending axially through the outer housing, and wherein the outer housing includes a first passage extending from the inner surface to the outer surface and a second passage extending from the inner surface to the outer surface; and a seal assembly disposed within the outer housing and configured to seal against a rotating tubular member extending axially through the throughbore of the outer housing, wherein the seal assembly comprises an inner housing including a first end, a second end opposite the first end, an inner surface extending axially from the first end to the second end of the inner housing, and an outer surface extending between the first end and the second end of the inner housing, wherein the inner housing includes a first passage extending from the inner surface to the outer surface of the inner housing and a second passage extending from the inner surface to the outer surface of the inner housing; wherein the first passage of the outer housing is in fluid communication with the first passage of the inner housing, and wherein the first passage of the outer housing and the first passage of the inner housing are configured to supply a lubricating fluid to a bearing chamber of the inner housing; wherein the second passage of the outer housing is in fluid communication with the second passage of the inner housing, and wherein the second passage of the outer housing and the second passage of the inner housing are configured to receive the lubricating fluid from the bearing chamber.
 21. The rotating control device of claim of claim 20, wherein: the first and second passages of the outer housing each include a check valve; and the first and second passages of the inner housing each include a check valve.
 22. The rotating control device of claim 20, further comprising: a plurality of fluid conduits in fluid communication with the first and second passages of the outer housing; and a sensor coupled to one of the fluid conduits, wherein the sensor is configured to measure at least one of pressure and temperature of fluid disposed in the fluid conduit.
 23. The rotating control device of claim 22, further comprising a stab plate coupled to the outer housing and including a fluid connector coupled to an end of one of the fluid conduits.
 24. The rotating control device of claim 22, further comprising a lubrication system coupled to the plurality of fluid conduits, wherein the lubrication system is configured to circulate lubricating fluid in a continuous circuit through the bearing chamber of the inner housing of the seal assembly.
 25. The rotating control device of claim 20, further comprising a sensor coupled to the outer housing and in fluid communication with the bore of the outer housing, wherein the sensor is configured to measure at least one of pressure and temperature of fluid disposed in the bore of the outer housing.
 26. A rotating control device for sealing an annulus extending from a subterranean wellbore, comprising: an outer housing including a central axis, a first end, a second end opposite the first end, an inner surface extending axially from the first end to the second end, and an outer surface extending from the first end to the second end, wherein the inner surface defines a throughbore extending axially through the outer housing; a seal assembly disposed within the outer housing and configured to seal against a rotating tubular member extending axially through the throughbore of the outer housing, wherein the seal assembly comprises an inner housing including a first end, a second end opposite the first end of the inner housing, an inner surface extending axially from the first end of the inner housing to the second end of the inner housing, and an outer surface extending from the first end of the inner housing to the second end of the inner housing; a first proximity sensor disposed along the inner surface of the outer housing; and a first sensor element disposed along the outer surface of the inner housing; wherein the first proximity sensor is configured to measure the rotational speed of the seal assembly in response to rotation of the seal assembly in the outer housing.
 27. The rotating control device of claim 26, wherein the first sensor element comprises a magnetic member.
 28. The rotating control device of claim 26, further comprising: a second proximity sensor disposed along the inner surface of the housing; a second sensor element disposed along the outer surface of the inner housing; wherein the second sensor element is configured to detect a leak in a sealing element of the seal assembly in response to leakage across the sealing element.
 29. The rotating control device of claim 28, wherein the second sensor element comprises a sensor element assembly comprising: a housing; a piston slidably disposed in the housing; a biasing member configured to bias the piston towards a radially inner position; and a burst disc configured to rupture in response to leakage across the sealing element.
 30. The rotating control device of claim 29, wherein, in response to the rupture of the burst disc, the piston is configured to be actuated into a radially outer position.
 31. The rotating control device of claim 30, wherein, in response to the piston of the sensor element assembly being disposed in the radially outer position, the second proximity sensor is configured to output a signal.
 32. The rotating control device of claim 30, further comprising: a transducer disposed along the outer surface of a sleeve disposed in the inner housing of the seal assembly, wherein the transducer is configured to measure the pressure of fluid disposed in a bore of the sleeve; and a transmitter disposed along the inner surface of the outer housing; wherein the transducer is configured to wirelessly communicate signals indicative of the pressure of fluid disposed in the bore of the sleeve to the transmitter.
 33. A method for sealing an annulus of a marine riser with a rotating control device (RCD), the method comprising: (a) coupling an outer housing of the RCD to the marine riser; (b) lowering a seal assembly into the outer housing of the RCD after (a), wherein the seal assembly is configured to seal against a drillstring extending through the outer housing and the marine riser; and (c) extending a plurality of locking pins radially inward from the outer housing into a receptacle in an outer surface of the seal assembly after (b) to secure the seal assembly within the outer housing.
 34. The method of claim 33, further comprising (d) flowing a fluid from an annulus disposed between the seal assembly and the outer housing through a port extending through the outer housing.
 35. The method of claim 33, wherein (b) comprises landing an annular landing profile of the seal assembly against a corresponding landing profile of the outer housing.
 36. The method of claim 33, wherein (c) comprises engaging a chamfered profile of an inner end of each locking pin against a corresponding chamfered profile of the receptacle of the seal assembly.
 37. The method of claim 33, wherein (c) comprises pressurizing a fluid passage extending through each locking pin to displace each locking pin into the receptacle of the outer surface of the seal assembly. 